The sticky note Crowley leaves on the spell says, "Bye forever you fools Kisses C"
When Bobby compliments Dean on his repair work on the Impala, Dean replies "I should do this professionally." Back in Season 2 when Dean was living out a wish in the episode What Is and What Should Never Be (2007), a still-alive Mary tells Dean he's supposed to be at his job at the garage, so in Dean's dream life he actually was working on cars professionally.
To distract a security guard, Dean asks him: "excuse me, you got any Grey Poupon?" It's a take on a famous 1980s commercial for the mustard brand "Grey Poupon". The commercial have been parodied in many films and TV shows.
Start of a new intro for the/now/the road so far and supernatural.