What's a superpower most people think is awesome but actually wouldn't be and what's your reasoning?

Time stopping.

Assume the air stops too, because why wouldn't it, then you might be frozen in place by the solid air. But even if you can apply a small force and move it around, getting it to go into your lungs consistently could be a real problem. Best case you could keep walking forward with an open mouth, leaving vacuum surrounded by extra dense air behind you. That would make for some real excitement when time resumes. And even in that case it would become increasingly hard to stay in the same area and gather enough air to breathe. The highly variable density as you take it in might cause problems too - depends on how/where it starts being affected by time as you take it in.

Light too, if nothing is moving relative to you, then nothing is expending energy to make light, so you'd be probably suffocating, and in total darkness, even outside (at best after 8 minutes and 20 seconds: If the light isn't stopped entirely then I assume the speed of light being constant would hold. Otherwise if it's not stopped and not at full C then it would be so heavily redshifted that seeing would not be feasible anyway.) And if light does keep moving while time is stopped, then when time resumes, the sun (and planets, etc) would blink out for a while, visible to everyone presumably.