There is a difference between being in a zone, and getting caught in a rhythm. Smart salesman, the kind who gets you to put your name down on the condo package after a two hour tour of property, even though your better judgment tales you not to, know all about something called the "yes momentum." This is a sort of rhythm that gets the customer into the habit of saying "yes." The psychology behind this technique suggests that someone in a yes momentum is much more likely to say yes to any given question than someone who has been saying no all along. This is same idea comes into play with a "calling momentum."
Even if you are playing $.10/$.20 Hold'em, you will notice a negative effect if you fall into a rhythm of calling. Perhaps you shouldn't have been in with this hand to begin with, but with a bankroll of as little as five dollars and pre-and post flop bet's sitting at $.10, it's pretty easy to call with just about anything on hope of developing a hand down the lane. Bets jump to $.20 on the turn and the river, however, and that's not counting any raises. If you just call one bet during each betting round, you've committed $.60 to this hand. And if you've committed $.60, then you are very likely to call any raises -- thinking, "well, I'm in this far, it's just another $.20 to see if I won." The guy with the nut hand loves this attitude.
Making a call during an online game of poker is much simpler than in a live game. You simply click the mouse, and since the pointer is likely hovering over the call button you don't even have to move the mouse. Problem is, if you fall into the hypnotic rhythm of calling, calling, calling you might end up losing a lot more than you think. Stay focused.