Flying
Oh-ho-ho, flying, now that's amazing.
I'd say that's probably one of the best things you can do in a dream, though actually it's harder than I thought it would be.
For me, the hardest part is actually taking off, which works with a varying amount of success, but when I'm actually in the air the feeling is mind-blowing and there's nothing like it.
You made a good point though Sheath, even when I know it's a dream, and I know I can't be hurt, I've never had the nerve to go too high.