While it does get discouraging when there are several people in the pot preflop and you have a large pair other than AA, a lot of times at low limits the donkeys are pushing some sort of ace, so their money in the middle means that aces are on the table rather than in the deck. If they don't have an ace, they probably have a pp worse than yours, so call or all in. If mystery man takes it you are sunk, but even if one of the smallies connects you could still win a side pot and come out ahead for the hand.