"I will die with no bullets in my holster." - Michael Jordan
If things aren't going your way -- customers not buying, coaches not puttin YOUR name on the list -- you can do a few things.
Question why this is happening. This is useful in that you can examine things, but ultimately unproductive. Every minute you spend examining, you're not doing anything.
Complain about what happened. This is neither useful nor productive. Avoid.
Do a whole lot more of what you've been doing until the desired outcome is produced. Given that it's productive, i.e. Making sales call, going on job interviews, trying out for teams, practicing your craft -- you are guaranteed to eventually succeed, quit, or die. Those are the only possible outcomes.
So if you're going to lose, miss sales and not make rosters, might as well have each one be a step on the way to success. If you quit, these will end up as wasted time because try led to nothing.
No one failed who never quit. Cliche, yes, but that's because there's some truth in there.