Boredom is a horrible thing and can force even the best of us into doing things that common sense tells us is a bad idea. While most of us are decent enough people not to go in search of under aged nookie, we may very well let it affect our poker game. At the poker table there can be long stretches where you don't see anything that resembles a playable hand. There is nothing more boring than folding over and over again.
Usually when you want to have a good game of chess, you look for a player at roughly the same level of skill as you are. If your opponent is a lot worse than you, it's boring. You easily trap him in your gambits, and you never feel like you are sweating. In poker, it's different. You should actively look for poorer players to play against - because you want to win money.