What if humans are one of the only species that has involuntary responses to emotions and aliens just find it really annoying?
Like you’re just relaxing, watching a horror movie with your crewmates, and it’s so scary your claws start coming out and your hair starts to fluff up— then suddenly, at the scariest moment, the human just starts making this godawful high pitched sound that makes your ears hurt.
Or you’re watching a comedy and suddenly the human just starts dying. Their breathing speeds up and they start clutching their sides and rocking around, all while making these little yelping noises— you’re just about to call the medics when the human manages to choke out that they are just laughing. Apparently what you took for death throes are actually this species’ normal reaction to funny stimuli. Your confusion then makes the human do it more and louder.
Maybe your human friend breaks up with their SO and you’re comforting them and they start doing it again and you think that you’ve cheered them up. But then, last time they made this noise, they were just breathing quickly— now they’re releasing all these fluids from their eye sockets and nostrils and, while you really want to comfort them because they’re your friend, it’s hard not to recoil in disgust.
Humans are just so loud! If they cut themselves they yelp, if they trip over they shout, if they stub their toes they swear. Species with sensitive hearing can barely be around humans at all, because just hearing them raise their voices in an argument is enough to cause headaches that last for hours.
Alien (and human) entrepreneurs make their fortunes selling noise cancelling headphones for aliens working on human ships.