I love running on Asphalt, even more than running on the track. The track is just too bouncy too me for some reason, and I can't really get that snap like running on asphalt. It must be heaven to run on an Indy 500/Formula race track!
I love running on grass, too, but for my long runs. I don't run fast on grass, because it is uneven terrain, and that can create a different problem in itself.
I don't run on concrete roads or sidewalks. Those are the worst surfaces to run on. The sidewalks are lopsided, uneven , and full of indentations. I see a lot of runners running on the sidewalk now. As oppose to years ago, majority of runners RAN on the road.
ASPHALT - GRASS- TRACK -TREADMILL ( just to get the mileage in). Those are my surfaces, with Asphalt being number 1
I hate gravel, or semi-gravel dirt roads. It's a slow drag on the legs, and just feels slow as hell.