My Life: The Unwanted Punchline

Alright, listen up, not-so-smart human! Explain bear is here to break it down for your little brain. When someone says their life is a 'punchline no one asked for,' they're not saying their whole existence is a funny story. Oh no. A punchline is the surprising, funny ending to a joke. So, this person is saying their life is the *unfunny, unexpected, and probably disappointing* conclusion to some big setup, and absolutely nobody wanted that ending. You, little human, probably feel like that after trying to assemble IKEA furniture, don't you?