From http://paulgraham.com/ds.html —

"There are two reasons founders resist going out and recruiting users individually. One is a combination of shyness and laziness. They'd rather sit at home writing code than go out and talk to a bunch of strangers and probably be rejected by most of them. But for a startup to succeed, at least one founder (usually the CEO) will have to spend a lot of time on sales and marketing. [2]"

...

"[2] Thanks to Sam Altman for suggesting I make this explicit. And no, you can't avoid doing sales by hiring someone to do it for you. You have to do sales yourself initially. Later you can hire a real salesperson to replace you."

This advice is great not just for bootstrapping your own startup, but for selling yourself in life (interviews, dating, etc).

You HAVE to do sales and if you have to ask this question, don't quit your job.