system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why it's so hard to hold back laughter.

Like when I'm in class, for example, and something funny suddenly pops into my head and makes me want to laugh but I can't simply choose to laugh or not laugh. I have to hold back the laughter. Why is this?
gpt
The euphoria of laughter is an involuntary emotional response. Just like you can't choose to stop your own heart from beating, you can't choose to not find an event funny/sad/scary/etc.

We have these responses because they benefit humanity through authenticity - imagine if you couldn't naturally laugh at things, but always had to decide to "fake laugh". There would be nothing truly funny, since any laughter is done out of a conscious desire to laugh. Same with our reactions to anything evoking a specific emotion - for the emotion to exist, we must react to it naturally.