I'm usually pretty sure of my decisions. I understand that every decision in life has its share of regrets attached to it. Every road not taken will have some sights along the way that you will miss out in life's lil' journey.
Apparently its not the same for everybody.
Also, how do you decide when to cut your losses and just get the hell out? "I cant take it anymore!" is rather subjective and momentary; how do you know for sure that its time to abandon ship?