Poker players like to talk about leaks, or flaws that cause them to lose, or leak, money. Don't showdown enough? Leak. Too loose preflop? Leak. Coldcalling raises? Leak. Not defending your blind enough? Leak. Fan of the Spearmint Rhino? Big leak. One of the best online poker handles I have ever heard was StripClubLeak actually. Heck there is a major function in Hold 'Em Manager called "Leak Buster" that most online players have access to these days.
So what's my biggest leak? Taking a leak. I probabaly miss anywhere from 2-20 hands a day on bathroom trips, and that's expensive.