I'll be in the garage is a reference to the show "Rick and Morty where rick and his lover call it off. He gets home and tells his family how life is meaningless and says I'll be in the garage, where he has a attempt of suicide.
Jake: Are you okay dude? That break up was pretty harsh.
Phrase; The funniest phrase in existence, even funnier than Pickle Rick, what many consider the funniest shit you've ever seen, even though it is not the case.