Laughter:

Quora:

"laughter acts as a status cue. It can be a form of showing someone that you think that they are clever or attractive."

"Saying anything funny is almost always a social risk. You'll risk that the person won't understand the joke, or that it might offend them. Someone who plays it safe all the time wouldn't dare throwing out a joke ... , and so by taking the risk a person is already showing a certain level of risk-taking"