Confronting stupid
Some gigs are process oriented: Set up a process correctly and the rest takes care of itself. It's challenging and frightening to get it right, but after that, you merely have to do the hard work of showing up each day. Do the work and you'll get the results.
Other jobs require a different sort of hard work: the guts to be wrong, a confrontation with the risk of being stupid.
The comedian who fears that each new joke might fail, the writer who has to say something new, the leader who must improvise, solving new problems on a regular basis. What makes this work hard is that it might not work.
More and more people now have jobs that require them to confront the risk of appearing stupid on a regular basis.