Superheroes are all about wish fulfillment. Nobody wants to be Peter Parker, a poor, friendless shut-in -- they want to be Spider-Man, the guy who does whatever a spider can, which presumably includes eating his enemies. However, there are some super powers that aren't as great as they might seem, and would actually make your life exponentially worse, if not flat-out kill you before you apprehended a single bank robber.
6Quicksilver Would Go Insane
20th Century Fox
Quicksilver is the Marvel Comics equivalent of the Flash, a mutant with the power to move at lightning speed. As a result, he experiences reality thousands of times faster than the rest of us. It pretty much makes him a god.
No question, this would be the best power to have in real life. You get a text from Mom saying that she's coming over, and you can clean up your whole apartment in less time than it takes to message her back "OK." You'd never miss another delivery, no matter how little time the FedEx driver spent between leaving a note on your door and sprinting back to the van.
But spare a thought for Quicksilver, whose entire life would be a hell of waiting for ordinary humans to go about their slow-ass business ... to the point where it's hard to imagine he'd maintain his sanity.
They kind of make a joke of it in Days Of Future Past. When the X-Men first meet him, Quicksilver has a difficult time defeating boredom, between playing a game of ping-pong against himself, playing video games, watching television, and pick-pocketing Wolverine, all within less than a minute. But they are drastically understating the problem. The comics go into it a bit more -- there, Quicksilver has a therapist, to whom he describes the nightmare of his day-to-day life, like waiting behind someone to use a banking machine or standing in line at Burger King.
"Whopper farts seem like they take days to leave a room for me."
"Nah, that's how it is for us, too."
But even that is barely scratching the surface. Remember, he can move so fast that bullets appear to hang in mid-air, and he thinks at that speed as well. He's able to make decisions, to be present in that moment, at a thousand or ten thousand times normal speed. In other words, he doesn't think of himself as fast; he thinks of the rest of us as statues. For Quicksilver, standing in line at a grocery store would last the equivalent of years.
Bleached hair and goatees are back in style -- that's how far ahead he is.
Also, forget about normal relationships. Conversations would involve waiting hours for the next word to come out. This isn't just an annoyance, either. The brain needs stimulation -- stick a prisoner in solitary confinement for a while and they quickly lose the ability to form rational thoughts. It doesn't matter that, unlike the prisoners, he's free to interact with other people, because we're not people to him. We're snails. He'd never find anyone he could socialize with at his own pace. DC would never give up the rights.
5Nearly Any Normal Activity Would Turn Bruce Banner Into The Hulk
You know that Bruce Banner's whole shtick is that he turns into the Hulk when he gets angry. Except that's not always the case. The current Marvel films establish that it's not anger which turns him into a huge green punch-monster, but his heart rate. Banner has to practice meditation, wear a heart rate monitor on his wrist, and avoid YouTube comments in order to keep his inner beast in check.
"Dislikes mean nothing, dislikes mean nothing, dislikes mean nothing ..."
The movies don't give this problem much thought beyond explaining why he can't have sex with a willing Liv Tyler. In reality, Bruce Banner's daily life must be much more difficult than we've imagined, even when bad guys aren't trying to kill him. Right away, there's the fact that not only can he not have sex, but he can't masturbate either. A quiet evening spent on PornHub would get him too worked up, and soon there'd be a fully-erect Hulk smashing through walls.
Those little pants are tight enough already.
There's also no easy way that Banner could stay as fit as Edward Norton, considering that any vigorous exercise will trigger the monster within. But maybe he eats right and uses one of those ab-electrocuting belts they advertise on late night television? Sure, but you still have the fact that running for the bus or rearranging the furniture in his apartment are probably out of the question for Bruce. He essentially has to live like an arthritic 85-year-old. But even the elderly/disabled person knows that the worst that can happen if they overexert is a broken hip or heart attack. If Bruce Banner struggles too hard with a bookcase, he's going to Hulk out and rip the building in half.
Think about how many times this would come up in an average day. What if his elevator is busted? We hope he has an audio book, because it'll be a slow climb up those stairs (with frequent breaks) if he's going to avoid exerting himself and shapeshifting into a being of pure destruction, putting hundreds of innocent lives at risk. He also presumably can't have any caffeine, and as far as entertainment is concerned, he should probably stay away from horror movies, because he wouldn't want to get too scared ... or excited ... or laugh too hard ... hell, better stay away from movies altogether.
Except for Ang Lee's Hulk. That would knock him out, easy.
And this is all the stuff he can control. He still has to worry about nightmares, which are a real possibility, considering he lives in a world where monsters and alien invasions are a thing. Hell, even getting sick is a risk, because even a fever will increase your heart rate. Shit, at this point it's probably easier to stay in Hulk form all the time. That sounds like the less stressful option.