What I notice a lot while online is a guy will preflop raise 2x the big blind at around $60 and I'll call with say a J-10.
The flop will be something like 3-10-7 and he'll bet $120 and I call. The turn is then a Q and he'll bet $360 and I call again. The river will be something. like a 5 and he then checks and I bet and then he folds and shows a A-K.
My point is guys will just bet random amounts counting on you folding and they'll do it all the way down to the river until you show the balls to call the big bets when they have jack shit.