In reply to Dandelion: My usual climbing partner actually finds the same, and like yourself is cool with climbing on a rope. In fact he flings himself off everything and anything with a rope, but bouldering on the other hand is not so cool.
On the other hand, I find I'm really cool with pulling weird moves in bouldering, but my confidence in extreme moves, run out on a rope, needs work.
Fair enough, sometimes you just don't want to fall off boulders if they're that high, but I find I might actually practice falling down onto the pad, full force if I need to, get the spook out of my head. Falling on my back on overhanging ground is sometimes a bit unnatural feeling, so I might practice that.