Another pitfall is over adjusting based on a small sample size. If you sit down at a table with someone for the first time, and they play a lot of hands and show a lot of aggression in the first few orbits, its easy to draw the conclusion, that this person is a maniac, and start to make big adjustments "to get after him". But when you then 4-bet him light and get it in, it turns out, he had KK, so he was just playing his hand. This relates to the point "its not personal". Just because someone 3-bet you from the blinds, last time you opened the BTN, and now he is doing it again, does not mean, he is light and getting after you.
Ive been playing alot of online poker, and alot of players tend to go all in pre-flop almost every hand. Id like to know how to play against "always all in" players.
@Sam you listen! its not my fault fish have their cards face down in the center of the table and then look at them for others to see, i play to win, im not a filthy casual!