First commentor missed the Cassandra side effect: you can do nothing to change it and no one believes you.

You can see a person's next move at the expense of generating negative causality, wherein large objects are attracted to you at high speed. See the man unwrapping a sandwich? Boom, hit by a bus/piano/anvil/whale.

You're the only one who is able to see the changes.

Edit: I decided that a superpower which only alters your perception is not really a superpower, so let me improve it: All drivers who have the same eye color as you will be able to see the changed colors. Other drivers will see the original colors. Enjoy!

Anytime you use this power, immediately afterwards you feel everyone in a half mile radius's feelings at 200% intensity at the same time.

But it hurts like hell and you are in pain the entire time you shapeshift

But you stink like a skunk every time you turn invisible.

You never get to use the power for your own enjoyment because people will never leave you alone…you will constantly assaulted with questions because everyone knows you have the answers. You have no peace.

You become completely physically disabled, almost a complete vegetative state, and can't physically do any of it.

The summoning makes you feel nauseous