There's a lot of things I hate about running on treadmills. I'm yet to find one that doesn't cramp my gait. I find the unchanging scenery, usually rows of televisions, extremely de-motivating. When someone is running next to me I can't accelerate off into the distance when I jostle loose a fart. In the last cardio room I was last in there was serious risk of hitting my head with every stride. It's also hard not to feel like a tit while wearing my sunglasses.