The theme with these is someone is about to do something that they will regret doing and another person saying "no, wait!" just as they do it.
1. Person One sees a bowl of oranges, says "hey, apples!" and takes a bite of one.
2. Person 1: "hey, apple slices!" about to rub one over his eyeball
person 2: "wait, there's lemon juice on those!"
A different type of sketch:
1: Man, I would kill for some chocolate milk! Will your mom buy some?!
2: only if it's fortified with vitamin c.
1: no problem!
2. (opens fridge) but we need to be out of all the other stuff we have with vitamin c.
2. There's about 10 lemons in here.
(cut to them quietly drinking chocolate milk and grimacing)
1: Man, I would kill for some meth!