How common is it once dating for the woman to suggest they are not compatible?

I've had this a couple of times, where the formula is the woman gives a long list of reasons why we were not compatible, I say I'm sorry you think that and she leaves teary eyed. I don't call them the next day and they hunt me down and ask why I haven't called - to which I reply I thought we had split up, then she says she didn't mean or think so important the things she had said last night and we get back together again. What is going on here and is this a normal part of the development of a relationship?