This is not really something that can be avoided. Just limit your losses when it does happen by folding when your opponent is showing enormous strength.

Also, I don't think you should be scared when two random number cards appear on the flop. It's likely that these are just blank cards that didn't help anyone. In fact, if somehow you know for a fact that your opponent has a middle or small pocket pair, and the flop comes A, 7, 8, 8-8 and 7-7 are actually the least likely hands for your opponent to have.