Min. reraises confuse me(late stages)

[John Hurst]

So here is a situation that occurs fairly often and I'm often surprised by what my opponent has. It's the late stage of a $55 or $109 tournament(level 5) and I've switched into aggressive mode. Raised several times in the last ten hands. Suddenly an opponent who I have no solid notes on min. reraises me. Against a tight player this most likely is a monster but what does it mean from a random party yahoo. I've been shown AA, A2, J10, utter trash. I would guess at the 55s it's 30% monster, 50% solid holding, 20% utter trash from a frustrated opponent. I know this in not a detailed question, but how do you deal with a generic player who reraises you for the first time? Folding 100% gives up way too much equity, IMO.