Perpetual Check
Every so often we'll see a forum topic here at chess.com along the lines of "hey, my opponent won't stop checking me so that I can finish beating him." The poster seems to think this is unfair, that he's being denied his right to win by a player who simply won't man up and take their loss. Unfortunately for the original poster, they are learning a harsh lesson -- If you can't protect your king, you're not winning.
Here's an example from a recent tournament game of mine. I was doing well in this game, but we were both getting in to time trouble near the end of the G/60 time control. My opponent was doing his best at counterplay against the h2 square and I nearly slipped up and allowed a perpetual:
Both players need to keep constant care of their king. If you're winning, safety first! And if you're trying to salvage a draw from a worse position, look out for the possibility of attacking the opponent's king. Being caught by perpetual check isn't unfair, it's called being outplayed.
