Hi,

You kind of answered it yourself when you said "it's what you can make the best of out five cards". A pair of threes is almost the worst possible hand when two higher pairs are available in the community cards - because three pair is impossible.

Assuming the fifth card in the community cards was a 2 and your opponent's highest card was a J, the best available 5-card selection is:

Your opponent's:

Q Q 5 5 J
Two pairs, Queens and Fives, fifth card J

Yours:

Q Q 5 5 3 *
Two pairs, Queens and Fives, fifth card 3

Then your opponent has the better hand - better fifth card (kicker) - and wins.

Hope this helps,
heyn

* You wouldn't select your threes as one of your pairs, because your opponent's "Queens and Fives" would be better than your "Queens and Threes".