A writer is used to, with few exceptions, delayed gratification. You wait for your book to be ready for others to see, you wait for the acceptance, you wait to see your book on shelves. There are times (through readings, beta readers, etc.) where your work is out there fresh and live. It is the jolt of rapid connection; one of the reasons writers keep blogs.
Actors, dancers, and singers are mostly about immediate gratification. They are out there in front of people gaining reactions to each move they make, each song they sing.
I love to sing and (have been told) am very good. When I was young, I wanted to be a singer. I had no trouble singing in front of anyone, even huge crowds. I thought I was the best thing out there (sad, but true) and didn't want to listen to much else. I feel different now and wouldn't sing on stage if you promised me a billion dollars at the end of it.
Part of the reason I changed was the type of gratification. Yes, if you're good, crowds love you. When you are bad, however, you know it and so do they. And, while you can have bad books or horrid reviews as a writer, you can put out the best work you can while taking as much time as needed. In short, your bad note of a book must be crafted as a bad note where your voice can just crack in a song.
The only thing about delayed gratification is when there is too little of it for good writers to see them through. They question what they're doing. They wonder what they're thinking. Even their neighbor's cat is glaring with accusing eyes and hisses to get a "normal" job so what... are... they... doing?
Other artists have this problem as well but, since writing is often solitary, it is even harder on us.
What type of gratification do you long for? Do you get enough of it? What keeps you going?