In tune
Of interest, has anyone else found themselves more 'in tune' with opponents and their hands after you fold? Why is this? Fold, then catch the BB exhale and raise. Or the 'hand over the mouth' and/or holding breath bet on the river. Or the stare and bet. Or the overcall. Or the player who looks at his cards and immediately his chips. So why don't we always catch this info. while IN the hand?
Perhaps we spend too much time planning our next move, instead of observing?
It's a tricky combination of concealing tells, while trying to observe them AND interpret them correctly. Is it a real reaction or a blatant practiced motion meant to confuse. Figure out what they want you to do, and then do the opposite, right!? Most players are decently good at concealing, yet over the course of a few hours and a moment of weakness they practically turn the cards face up. At this moment, you can only hope you are in the hand, heads up, and paying attention. Unfortunately we are often looking at our stack, or the board, counting the odds, planning the moves... and not reading the signs.
Perhaps we should try a combination of observation and planning? The Full Tilt commercial with Phil Ivey is a great example. His mind is racing through odds, numbers, information about the hand and how it played, etc., all while STARING at his opponent! He watches each motion, calculating pieces of the puzzle, and puts it all together announcing "I'm all in". Coolio.

