Superman can move planets! Right... who wouldn't want to do that? But imagine what he must go through on a daily basis. RESTRAINT. With that kind of strength, imagine how much he has to hold back! Have you ever tried to handle a brittle dried flower without breaking it? That is what Superman has to endure on a daily basis while trying to make it seem effortless. Ponder about that.
He can move at such radical speeds that to him it appears that everything else is standing still. You know when you were young and there was that one kid that couldn't really read? So he stuttered and it took him forever to get through a sentence and you grew impatient and made fun of him? Well, that is what Superman has to go through everyday with everyone he meets, except for his buddy The Flash. Long work day got ya' bogged down? Imagine his.
I gather that he can control them. I get that. But there's smells that sometimes are just too in your face to ignore. Think about when you're entering a bathroom and the person before you bombed it... would you really like a super smell then?
Super sight? Okay, there's no real downside to heat vision or X-ray, at least none that I can think of.
How about super breath? Controlling your breathing is unnatural. Supes has to add that to his list of daily restraints.
What other downsides are there? Do share!