Have you been fooled twice before?

It means that if we don't learn from our mistakes, then it's our fault. Say I asked to meet you somewhere. I never show up, and you wait for about an hour in the cold before you give up on me. I call you again, a week later and the same thing happens. Technically, it would be my fault, but the moral of the story is also like that saying, if a dog bites you once, he'll do it again. Okay, well that one is actually more for people that get beaten or abused, but still. Next time make me meet you at your house, or you come to mine. If there's a chance I won't show up a SECOND time, well... shame on you. Both of us, really. But still, it's an old saying.