(While playing Texas Hold'em) Because I'll scratch my neck, puff on my cigarette, or sip on my beer instead of focus on my hand. Since I know those are my tells though I try to avoid doing them when I'm bluffing or purposefully doing them when I have the best possible hand to trick people in to thinking I'm bluffing when I'm not. Works rather well sometimes.
OT: Extra tactic, if you want to mess with people, tell them that you know their tells and then give them a false one like "you never drink when you're bluffing". Then sit back and watch them sip a lot or actually chug when they're trying to throw out false tells. (I know they didn't do that to me because I win the hand when I do it).
Gitsnik said:
My fiance can usually tell though, because I have to smile when I try it on her, so it just never works out.
Yeah, I laugh when trying to lie to certain people but I also can't help from laughing when what they're saying is ridiculous or they try to do a "serious interrogator face" so they think I'm lying when I'm not. So, they just give up trying to tell.