system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the evolutionary purpose of laughter?

Why do we laugh?
gpt
Not everything has a evolutionary purpose. Evolution works by a random mutation occurring and it not being detrimental enough to prevent that animal from reproducing. Evolution does not have a goal, and does not seek "the best" for something. 

As for why do we laugh? We are social creatures and laughing helps to build/reinforce social bonds by expressing happiness to the group.