Tea bags are terrible. Dreadful creations.
Go for the loose leaf stuff. You can get high-quality, organic stuff for cheap on Amazon.
Here's the difference: properly steeped green tea in most varieties is mild, even lightly sweet. I'm a supertaster, so you know I'm speaking truth here. If there were bitter, I'd taste it ten miles away.
I have a hub somewhere about the most popular varieties of green tea, how they taste, and how to steep them. Because steeping matters. It really, really does. And also: tea bags suck and usually cost far more than loose leaf.
But then, drinking the same thing is bound to get boring, period. The others have suggested honey and lemon, but I'm about to rock your socks off here:
(1) Try a drop of raspberry extract or even better, a couple lightly-crushed raspberries. Give your cup a little stir. Prepare to be dazzled.
(2) If you're drinking a very mild green tea, toss in a slice of apple as it steeps.
(3) Try 1/4 tsp vanilla and 1 tsp honey. And not imitation vanilla. Real vanilla.
(4) 1/8 tsp Nutmeg, 1/4 tsp Cinnamon, and 1 tsp Honey tastes like heaven.