Online when you make a bad play no one is there. But live you have 8 other people sitting there judging you. Face it you play better live because you can get immediately judged LIVE.
Dear weros99, your question is very interesting!
In online poker the psychological pressure is less intense. With the cards in hand, keeping an eye on the opponent is a lot of psychological pressure. I only play online as I don't have time to be in places where people play in person.