The most common powers being discussed in this thread appear to be mind control (obviously), telekinesis, time manipulation and immortality (though I think that was only mentioned once).
People have already pointed out the errors of mind control such as being unable to stop mindless objects and diseases from killing you but one funny thing to note is that often when mind control is used on say, the hero, they overcome mind control through either simple will power or extreme emotion. This is plausible as to overcome mind control they could just focus all thoughts onto a single task (such as beat the tar out of you) and surges of emotion effect responses in the brain making it harder for the controller to keep up with all the changes.
Telekinesis is dependent on how strong and in what form you have it. There are three types of telekinesis; the ability to influence a stationary object, the ability to influence an object in motion, and the ability to influence living things (this is not mind control, this is more along the lines of curing a disease or making a body part move differently rather than making them make their body move differently). Simply having telekinesis does not give you telepathy or the power to see into the future or know what?s around you. Furthermore it would probably take a great deal of concentration to do more than one of these different variations at once.
Time manipulation is a weakness in its self, mostly because the possibilities in life are endless. Even if you've been to the future to know what?s happened there's a chance it won't happen like it did in the future and could be completely different. Time travelling into the future can't be done because the future is undetermined. As for travelling into the past, well if you're dying you'll have to be very quick about warning your past self, and also it would be harder to concentrate on which time period to warp to in both the heat of the moment and whilst you are in pain. Also changing the past is risky as even the smallest of things can change the greatest of events.
Finally immortality, defined simply as cannot die in any manner, is the worst super power to have, ever. If you live forever you have to see all your love ones die and when you have new friends you also have to watch them die and the process repeats till you're driven insane. Also immortality is not the same as regeneration so even if your body was dismembered you wouldn't be able to put it back together, you'll just live in eternal agony, incapable of doing anything.
The final thing that scuppers most of these powers is morals. Morals prevent any of these superpowers unless you were evil or have some really twisted morals. Anyway nothing else to comment on so here's my post.