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."