The epic Butt Monkey-ness that Peter has gained by the end of the film.
Ethan panicking after shooting Peter.
Ethan rescuing Peter.
During the rescue, the Mexican cops are yelling "Pull over!" in English and Ethan responds, in Spanish, that he doesn't speak English
Ethan threatening the handi-capable clerk with his hairbrush.
The contact high and it's results.
Peter, who's been avoiding the possibility that his expectant wife is pregnant with the lovechild of hisBlack Best Friend, bursting into a delivery room he thinks she's in and the first thing he sees is... a newborn black baby. Cut to an understandably bewildered black family who quickly kick him out and a huge look of relief on Peter's face.
Peter sucker-punching the obnoxious little son of the drug dealer. It's so wrong, but you will laugh so hard it hurts. And don't forget the fact that when the drug dealer returns, Peter and the boy act like nothing happened. Capped with Peter donning his sunglasses and pointing at the little boy as if to say, "Know your role, punk."
After falling asleep at the wheel, Ethan send the rental car flying off a bridge, completing a barrel roll and almost completely destroying the vehicle, not to mention almost killing the two of them. After a brief moment in which Peter struggles to determine how injured he is and how lucky he is to be alive (during which he starts to cry), Ethan reaches over to the glovebox, pulls out the rental agreement, carefully reads it, and announces, "I have coverage."
The entirety of Peter's rant outside the hospital after Ethan almost gets them both killed in a car crash. Pick any line and I assure you it's gold.
Special mention also goes to the scene afterwards where Peter's actual friend convinces him to calm down and make things right with Ethan.
Peter: Alright, I've had some time to calm down—
Ethan: Are you ready to apologize?
Peter: (enraged)Apologize?!FUCK YOU!(turns to his friend) Let's go!
And then there's the classic, "If you hand me that dog, I will rip it in half."