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^ That is bluffing.
Bluffing sometimes made your lucky day but not all the time, if you have opponents that have the same technique used, it will probably not work because both of you pretending about the emotion.
But I don't know how it will work in online poker games if your opponent is online, there is no bluffing and your luck depend on the cards that you get. I don't know how effective poker game online courses are right while it is free over the internet, I even watch a different tutorial on Youtube and try my skills using an app that is playing poker for free.
I disagree that in online poker you can't bluff, and your game depends only on the cards that you get. Far from it. In fact, in online poker you can do all the things you do in real life games, and that's why the same people who are doing good in live games are doing good in online poker as well.
My theory is that your face expression is not that important. What's important is the time you take before the action and the size of your bet.