apprentice; to answer your questions, YES! It has been my experience that even if you flirt with some women and then not ask them out within a short time period they get all offended and resent you for it, absolutely. It is probably a rare thing that a guy can be so perceptive as to see this so congratulations!
As far as getting one chance only and never again, I agree with sapphire, it depends on the girl. I have had girls that (looking back on it) gave me one chance, but I didn't do anything about it soon enough, so that was it. I just asked a girl out last night that has been giving me interested signs for a year, she didn't say yes YET, but she didn't say no either!, so it totally depends on IL and the girl's ego. A girl with High IL will no doubt give you some slack providing she's not the type that gets offended easily.
As far as getting over the ego thing, that's the tough one, and one that I would like to know the answer to as well, I could then go back and correct a dozen missed opportunities. But my thinking is, you will have to REALLY work for a second chance with these particular girls. CONFIDENT PERSISTENCE, is the term that suits here, so you want her?, then do WHATEVER it takes for HOWEVER LONG it takes to do just that. BELIEVE that you can get her, and so PROVE to her you wanted her all along!