Your opponent is representing a set. He limps in ep, calls a raise, bets weak on the flop hoping for a raise, then pushes after you define your hand because he knows that normally his set gets paid off here.

Unless he's been doing this every other hand, I wouldn't call your fold gunshy. I'd call it smart poker.

Got any better examples? Because I know the feeling. Becoming gunshy happens to me when I'm running really bad. It usually takes me a couple of winning sessions to get back on track. Just play through it and think out your difficult decisions. Playing cautiously does not always mean weak.