I thought the match was a joke as Serra was not half the fighter that GSP was. Then I was pissed off because the lesser fighter managed to pull off the upset. Everyone underestimated Serra including GSP.
People always say that it is a fight and anything can happen, not often does an outcome show this to be true in such dramatic fashion.
Most of GSP's opponents would smoke Serra like a joint. The rematch clearly demonstrated who the superior fighter was however, GSP learned not to stand and trade with heavy handed fighters no matter how much better he is technically.