False tells vs. real tells
If I think someone's clever enough to show me a false tell, I would be tempted to not base decisions on perceived tells. I think it's very important to observe a player's tendencies for a while first; this will help cut down on the chance that a player is fooling you with some one-off false tell.
Originally Posted by jaxpaboo
Also, as Caro points out in his book, if a behavior seems more "on display", then it might be because a player is consciously doing it. Honestly, though, it is pretty rare that I see someone pulling a decent false tell. I recommend in my book against them for several reasons. Good players will just not often get involved doing stuff like that, and it would only be the good players who might do a convincing job of a false tell.
In a lot of cases, a player who thinks he is giving a false tell is actually just giving a tell. For example, a player who's got a very strong hand and decides to suddenly get creative and act like he's weak may be giving away his strength to an observant player, just because whatever act he is putting on is different from his usual behavior he would usually have without a strong hand. So for example, a player who is acting all timid with AA (or whatever he believes faking weakness looks like) appears different than the previous spots where he didn't have AA. If he had been stoic in previous hands and then all of a sudden he's acting in some weird way, his attempt at a false tell has, in this case, become just another tell.