Boring poker, or "study" time?
You've all made some good points: playing good poker is boring. But for a new player, or when you are playing with new opponents, there is plenty to keep you busy. If you're in a hand, you are busy with that. But, if you are out early, why not spend the time to try and learn about the folks still in the hand? It is tougher online, but you can still keep track of how they stall, their betting patterns, and how they react to a raise, call, overcall, or reraise. Of course, in a live game, you can watch them at the same time, looking for tells.
I do play multiple tables at times, but only when I have found that I have some "fish" at my table, and I don't need to do quite as much studying of the players. Otherwise, I like to spend my time learning. The main difference in a live game and online is that in a live game, I usually play against the same folks week in and week out, and learn their habits. Online, I may play the same person twice in a month, so I have to learn all about them as fast as I can.
If you spend the "down" time watching as intently as if you were in the hand, your poker success will improve, guaranteed.