As the duo make their quick getaway from Miles' mother's house, notice he's wearing white loafers. Later, as he's getting dressed for the dinner date in the hotel room, he informs Jack he's only brought his brown shoes along for the trip.
In the scene at the bowling alley, the woman at the table with Miles (Sienna's grandmother?) is smoking. Smoking indoors is illegal in California (although it is possible the bowling alley simply was not enforcing this rule).
When Miles pours the wine from the spit bucket at the tasting room over his head it drenches his shirt and pants. In the subsequent scenes, the wine stains have dried, but the clothes have actually been changed. There are stains on the shirt, but there are not enough to match the original incident and the pants have no stains at all.
On Wednesday when Miles and Jack pick up the girls, Miles and Jack are in front with the girls in back. In the next shot, Jack and Maya have switched places (there is a deleted scene that would explain why).
When Miles is checking his phone messages from the motel room, the voice instructions tell him to "enter his password and press the pound key". The sequence of digits he presses ends with one of the keys on near the top of the keypad; the pound ("#") key is on the bottom row.
Miles drops off Jack in front of Christine's house. You see them unload the golf clubs and wine boxes on the left side of the porch, close to the door. In the next scene you see Miles in the car observing Jack who knocks on the door. It appears that the golf clubs and boxes of wine are not in the scene when Jack knocks and the door is opened by Christine. At the end of the scene the boxes and clubs can be seen to the far right side of the porch, further away from the door.
In the scene where Jack tells Miles he thinks he's in love with Stephanie, Miles's arms are crossed over, then his fingers are laced together in the next shot, then his arms are crossed over again two shots later.
When the two guys first meet Stephanie, in one shot, we see her in the process of half-filling Miles' wine glass. It then cuts to a continuing shot from behind, but his glass is only quarter full as she continues to pour
Miles and Jack are drinking at the Hitching Post. Maya comes around and joins them. At this point hands jump all over the place. Miles arms are crossed at different variations without enough time for him to move. Jack is holding a full glass to drink, and then immediately has pushed it out for a refill. In one shot Maya's arm is up, in the reverse shot, her left arm is down.
While Miles makes his protest of Cabernet Franc and Merlot well known, the bottle of 61 Cheval Blanc is from Bordeaux, a blend of Cabernet Franc and Merlot. This is entirely logical: Merlot from California is widely considered to be inferior; Cabernet Franc is a grape used primarily in blending. On their own, both wines are well less than stellar. Cheval Blanc is indeed a Bordeaux blend of Cab Franc and Merlot (and a few other grapes), but in their Bordeaux incarnations their grapes produce an excellent red wine. Indeed many Bordeaux producers use the two grapes in their Bordeaux blends; the California incarnations of the two grapes are just not all that great. Miles' sentiment is shared by many wine lovers around the world - even those from central California.