Stress
On the surface, you'd think this career doesn't come with a lot of stress. Standing around telling jokes? For reals? How is that even a job?
The truth is that performing stand-up comedy is extremely high-stress. Hear us out.
First of all, most people cite a fear of public speaking as greater than their fear of dying. (Stand-ups frequently do both simultaneously.) Just because someone gets up on stage doesn't mean they're immune to it. In fact, if you go to an open mic, you'll be amazed to see how many of the comics look absolutely petrified to be there.
Second, the job itself—the grind to lock up gigs, the difficulty of having to squeak by on such little pay, the continual reminders in your material of how crappy your life is, the loneliness of touring on the road surrounded by other degenerates—it all adds up to a whole bunch of stress. Which is why comics often turn to things like booze and drugs as a way of dealing with it. A bad way of dealing with it, we'd like to mention.