Success, in my view, is the willingness to strive for something you really want
It's perfectly okay to want to quit - as long as you don't.
Maybe you can't play over your head at all. Maybe it's just potential you never knew you had.
Profit isn't and shouldn't be the mission of business. The mission of business is to help people. To help your customers, your co-workers, your employees, and your partners. Success is not a number - it's not X dollars or Y customers - it's a measurement of VALUE.
If it's not fun, you are not doing it right.
None of us really pushes hard enough. People always talk about playing over your head when you are up against someone really good. Maybe you don't play over your head at all. Maybe it's just potential you never knew you had.