A recurring gag featured in the show's outtakes involves the cast and crew laughing hysterically at the mention of the phrase "three-hole punch." According to James Roday, the gag began with a script written by Tim Meltreger, which included a joke about a three-hole punch. During filming, Roday misspoke the line as "three-hole puncher." Meltreger called for a cut and raced onto the set, then insisted that Roday read the line exactly as scripted, because, in his words, "Three-hole punch is *way* funnier than three-hole puncher!" Subsequently, it became a running joke on the set: someone says the words "three-hole punch" while shooting and the cast and crew all pretend to laugh as if it's the funniest thing they've ever heard.
With the exception of Emilio Estevez who appeared in name only as one of Shawn's aliases, and Paul Gleason, every main actor and actress from The Breakfast Club (1985) appeared in the series. Judd Nelson appeared in the episode "Death is in the Air", Molly Ringwald appeared in the episode "Shawn Interrupted", Ally Sheedy appeared in the episodes involving the Yin-Yang killer and "Psych: The Musical", Anthony Michael Hall appeared in "No Trout About It" and the beginning of season eight, and John Kapelos appeared in two episodes ("Santa Barbarian Candidate" and "1967: A Psych Odyssey").
Kirsten Nelson was pregnant in real-life, when she auditioned for her role as Interim Chief Karen Vick. During the first few episodes, she gave birth; from that time on she had to wear a fake pregnant stomach for the remainder of her character's pregnant period, to compensate for her diminishing belly.
Shawn (James Roday) and Gus (Dulé Hill) almost always wear opposing shirt patterns (between plaid and striped). Shawn almost always wears short sleeves, while Gus rolls his sleeves to three-quarters. Even in episodes where they are wearing sweaters, the undershirts will alternate. In some episodes, Gus will wear a pinstriped suit, while Shawn wears a plaid shirt.
Gus always used Microsoft-related products, while Shawn always used Apple-related products. This includes their phones in later seasons, where Gus can be seen using a Windows phone (for example, season seven, episode six "Cirque Du Soul"), and it's well-known that Shawn uses an iPhone. Gus always uses a non-Mac PC, and Shawn uses a Mac PC. Except for some episodes, where an Alienware laptop can be seen on Shawn's desk. This can clearly be seen in the episode "Forget Me Not".
According to his "MySpace" page, the following is a list of jobs that Shawn Spencer held before becoming the CEO of Psych: Newport Sailing Assoc., Newport Beach, California, U.S., Assistant Race Chair 2006; English, Inc. Kho Samui, TH Teacher, TEFL 2005; Comerica Park Detroit, Michigan, U.S., Concessions Vendor 2005; Apollo Agency Seattle, Washington, U.S., Foot and Ankle Model 2005; Ben and Jerry's Burlington , Vermont U.S., Customer Service 2004; Minute Maid Park Houston, Texas, U.S., Concessions Vendor 2004; Aquablanca Expeditions San José, Costa Rica Raft Guide 2003-2004; U.S. Cellular Field Chicago, Illinois, U.S., Concessions Vendor 2003; Flynn Special Events Santa Barbara, California, U.S., Event Planner 2003; Mo's Outdoor Decor Santa Barbara, California, U.S., Christmas Light Hanger 2002; Graceland By Night, Inc. Memphis, Tennessee, U.S., Tour Guide 2002; Miller Park Milwaukee, Wisconsin, U.S., Concessions Vendor 2002; Oscar Meyer Wienermobile Madison, Wisconsin, U.S., Driver 2001 - 2002; Safeco Field Seattle, Washington, U.S., Concessions Vendor 2001; Feedback, Inc. Santa Barbara, California, U.S., Mystery Shopper 2000-2001; Turner Field Atlanta, Georgia, U.S., Concessions Vendor 2000; Assemblyman Skip Warner El Paso, Texas, U.S., Constituent Relations 1999; Camp Durango Silverton, Colorado, U.S., Water Ski Instructor 1998-1999; Barrett's Mardi Gras Universe Algiers, Louisiana, U.S., Construction 1997-1998; Hampton Inn Austin, Texaa, U.S., Desk Clerk 1995-1996; Pacific Emerald Cruise Lines San Pedro, California, U.S., Lifeguard 1994-1995. During one episode, he mentions having worked at Meineke for two afternoons.
The casting team for this show appears to have a marked love of '70s and '80s television shows and movies. They cast stars from television shows Growing Pains (1985), Family Ties (1982), Family Matters (1989), The Cosby Show (1984), Moonlighting (1985), Married with Children (1987), and Good Times (1974); and movies The Breakfast Club (1985)*, the Star Trek film franchise, Ferris Beuller's Day Off (1986), The Princess Bride (1987), Pretty in Pink (1986), The Rocky Horror Picture Show (1975), Ghostbusters (1984), Ghostbusters II (1989), La Bamba (1987), and Revenge of the Nerds (1984). This is far from a complete list. *Four of the five students in The Breakfast Club (1985) have appeared on this show. The only one not cast is Emilio Estevez, although Shawn uses this name as a cover while investigating in season three, episode thirteen, "Any Given Night at 10PM, 9PM Central", as well as season eight, episode four, "Someone's Got a Woody".
A running gag in the show is that Gus and Shawn will frequently say "C'mon son!" when something strange, surprising, or silly has happened. This phrase was coined by media personality Ed Lover. In the season eight episode "Remake, a.k.a. Cloudy...With a Chance of Improvement", Ed Lover guest starred as a bailiff, telling Gus to "Come on, son" as he attempts to escort him from the courtroom. He also appeared in the season six episode "Last Night Gus" as himself.
The vampire themed episode "This Episode Sucks" season six, episode three features three vampire themed guest stars. First is Corey Feldman from The Lost Boys (1987), and the second is Tom Lenk from the television show Buffy the Vampire Slayer (1997). The third is Kristy Swanson, who starred in the original movie Buffy the Vampire Slayer (1992). As Corey Feldman turns around to the camera, "Cry Little Sister" from The Lost Boys (1987) soundtrack is playing in the background.
Several Psych cast and crew members have crossed paths before. Tim Matheson, Freddie Prinze, Jr., Carlos Jacott, Elden Hensen, Tamara Mello, Rachael Leigh Cook, and Dulè Hill appeared in She's All That (1999). Anna Paquin, Gabrielle Union, and Paul Walker are also mentioned, but don't make appearances.
In the season six opener, "Shawn Rescues Darth Vader", Ambassador Fanshawe, played by Malcolm McDowell, comments on how bad Shawn's English accent is. When Shawn is asked by the Ambassador where he gets his terrible accent, Shawn tells him it was from Phineas and Ferb's grandad. McDowell played Reginald Fletcher, the grandfather of Phineas and Ferb.
In season five, episode two, "Feet Don't Kill Me Now", Gus teaches Detective Carlton Lassiter how to tap dance. Lassiter is played by Timothy Omundson, who previously played a riverdancing evil leprechaun Seamus McTiernan in the Disney television movie Luck of the Irish (2001).
Family Guy (1999) pays homage to this show in season eight, episode twelve, when Peter pretends to be psychic, and helps the police solve a crime. This is the whole basis of this show, and Peter even says he will psych out the criminal, which is a line in the "Psych" theme song.
In the episode "100 Clues" (season seven, episode five) Christopher Lloyd says "Great Scott!" This was his catchphrase from the Back to the Future trilogy. Lloyd's name in the episode also happens to be "Marty".
In this show, Timothy Omundson plays Carlton Lassiter, and is named after two memorable characters from different '90s television comedy series. The first one is Carlton Banks, played by Alfonso Ribeiro in The Fresh Prince of Bel-Air (1990). The second one is Paul Lassiter, played by Richard Kind in Spin City (1996).
In an early episode, people tell Gus he looks like Bud from The Cosby Show (1984), and in a later episode, we meet Gus' mother, who is played by Phylicia Rashad, who played Clair Huxtable on The Cosby Show (1984).
A running gag in the series, is that Gus (Dulé Hill) played Bud on The Cosby Show (1984), a character who was actually played by Deon Richmond. Dulé Hill played a character named Preston in She's All That (1999). In the parody film Not Another Teen Movie (2001), the parallel character satirizing Preston (Malik), is played by Deon Richmond.
Shawn is a San Diego Chargers fan. In one episode, he is seen wearing a Chargers sweatshirt. In "Forget Me Not", he screams "Run Ladanian!" while playing video games, as Gus walks in. While referring to Chargers ex-Running Back Ladanian Tomlinson.
In the episode, "Shawn Interrupted", Gus goes undercover as an orderly named Suggs. This was similar to the name of his character in Sugar Hill (1993). He played seventeen year old Romello Skuggs, who was also Wesley Snipes' character.
In season one, episode fourteen, "Poker? I Barely Know Her", Shawn states that he is not a jewelry man, yet, throughout the entire series, he has worn three different necklaces for multiple episodes, or even seasons, at a time.
In season three, episode thirteen, Shawn mentions he was going to retort to Lassiter with a line from Night of the Comet (1984), starring Catherine Mary Stewart. Catherine also starred in Weekend At Bernie's (1989), with Jonathan Silverman. Jonathan Silverman was in the next episode, as Lyin Ryan.
The trivia items below may give away important plot points.
In the final episode, "The Break-Up", Chief Vick and Juilet mention that they can't hire Psych as a consulting team, because they already have a guy, and he is "alphabetizing the pantry as we speak". This is a reference to the television show Monk (2002), which is set in San Francisco, California.
A running gag in the show, is that Lassiter constantly mentions a "Detective Dobson", but we never see him. Another running gag, is that Shawn is told he looks like Val Kilmer. In the season finale, Detective Dobson is shown, and he is played by Val Kilmer.
In the final episode, Gus calls his new boss, Mr. Richmond (played by Deon Richmond) "Bud". This was a nod to the character Richmond played on The Cosby Show (1984), Kenny a.k.a. Bud. This is also the culmination of a running gag, in which Shawn tells people that Gus played Bud.
In the pilot, Shawn tells Gus that he will never tell anyone that he's not psychic. Throughout the series, he never does completely admit it to anyone, besides Juliet O'Hara, who discovered it by herself in "Deez Nups". The closest he gets to telling anyone, is in the finale, on his video to Lassiter, who stops and destroys the disc, before Shawn finishes his admission.
In the final episode, Shawn goes up to San Francisco to follow Juilet, he mentions that he can work up there for the SFPD, and Chief Vic says that they already have a guy, and he is pretty good, and that he is in the kitchen rearranging the cereal boxes, this was a nod to Monk (2002).
In season seven, episode one, "Santabarbaratown 2" when the FBI Agent is at the police station, Shawn says to him, "I don't get your peachy, Anthony Michael Hall-ish face! What is with his face?" Anthony Michael Hall plays Harris Trout, intern Chief of Police in season eight.
In season two, episode fourteen, while pinning the murderer, Shawn says "From the halls of Montezuma!" This is a reference to the first line of the U.S. Marine's Hymn which begins, "From the halls of Montezuma, to the shores of Tripoli."