Human impulses and fears can make you give up on your vision way too early, and for the wrong reasons.
Quitting too early and on impulse is boringly human, anyone can do it.
However, quitting according to intelligently prescribed criteria is a successful business decision, and allows you to survive the experience, learn a lesson, regroup and try again.
So, have an explicit exit strategy in your business plan spelling out exactly what your criteria for quitting are. And each time you see your fear and doubts take over your thinking, revisit your written criteria and re-assure yourself again that your fears are unfounded.
Well thought out quitting criteria and strategies keep your impulses and fears in check. Sticking to these criteria can save your business from premature decisions. And if it happens, your quitting will be planned and orderly.