I am 6'6. I wouldn't change it, but there are many annoyances and disadvantages.
Flying on a plane is an awful experience (no leg room). Clothes can be hard to find. Cars that accommodate you are hard to come by. Furniture isn't made with you in mind. People are annoying about it (How tall ARE you? Did you play basketball?). People stare. You have to duck and hunch sometimes ... sometimes forget and bang your head. When I was a kid, people would assume I was a lot older than I was... like aren't you too old for trick-or-treating (or whatever). Too tall to be an astronaut.
Running-wise, you are naturally heavier and have a harder time dissipating heat (most of my PRs are set in the 30-40 degree range). Drafting is also less advantageous if you're a foot taller than anyone else. People who know nothing about running assume the opposite (longer legs means fewer strides, therefore it's easier, right?).
As others have said, tall people usually don't live to a very old age. I have naturally low blood pressure, and a low heart rate, so I get head rushes if I get up too fast (common with tall people). I've blacked out and fallen twice in my life from this.
Good things: I could dunk in 8th grade. I could ride rollercoasters, etc., before others. You can be a hero sometimes and reach something for a stranger. Stereotypically, women like tall guys. I am easy to pick out of a crowd, and I can see over the top of the crowd. (Downside is I feel guilty for blocking others' views.)