Why not just stay home? Why not just buy a decent bag of freakin' peanuts?
As insane as it may sound, most bad singers don't know that they sing badly. Again, if you've ever been to karaoke, you absolutely know this to be true. You may even have a friend who has deluded themselves into thinking that when they bust out "Cat's In The Cradle" on stage, it doesn't actually sound like three cat's in the blender. For those who haven't been to karaoke night, watch any singing-based talent show. American Idol made its mark by spending a few episodes every season mercilessly mocking the tone-deaf and musically unstable. These people aren't donkey-brained gluttons for punishment; they seriously don't understand what they're doing.
If singing isn't your bag, look at the world of writing. When this internet thing finally caught on, the world of the professional writer exploded. I would assume that there are easily tens of thousands of people writing for money today who could not have done so without online publishing being a thing, and who otherwise would have all been selling oranges on the freeway off-ramp alongside me. So probably all of these writers assume they're awesome. How awesome? Maybe even as awesome as me.
And how do you get awesome? Space poop and racist porn, baby.
I've been writing since I was in grade school -- I used to write short stories all the time. In high school, I wrote really preposterous and vulgar noir detective stories featuring my friends as characters, and everyone thought they were funny because I'm super-likable and charming and not desperately sad and in need of validation. Like the karaoke singers, I was bolstered by the support of my friends, who made me believe I was really good, probably as part of a master plan to make me shut up. And of course, as it turned out, I am good enough to do this for a living now. Look at you, reading my work. You just proved me right. But am I as good as I think I am? I have an entire finished novel on my hard drive that an ever-growing number of people in the world of publishing have turned down that suggests maybe I'm OK, but not some kind of Walt Whitman / Chuck Palahniuk writing-Voltron. After all, it's hard to objectively look at yourself and think, "Yeah, I'm pretty average. Go team!"