Is okay to ride your bike with your dog?

So I've seen people doing this sometimes, they either hold their dogs leash while riding their bike, making their dog run next to them, or I guess they tie it to their handle bars. Is this cruelty? I guess I just want personal opinions unless there is a fact answer. Is it choking or hurting them? Is it mean to make them run that fast or not? I wasn't planning on doing it I was just wondering though. Do you know/think they enjoy it at all?