If you wear headphones, your pocket is too full. It's already got your phone in it, and then, to keep it from flopping useless against your thigh all day, you've stuffed the remainder of your overlong headphone cable in there as well, maybe rolled up neatly or wrapped around the phone, but most likely just jammed in like a handful of shoelaces. This isn't really ideal. It's also highly fixable.
The answer is that you just, you know, buy a new cord. A cheap new cord! One that's shorter. Really, they're like five quid on Amazon, maybe ten, or two. You can even get a different colour and flash. All of them work (and sound) exactly the same. Yet it seems pretty uncommon that anyone actually does this. Which raises the question, WHY THE HELL NOT?
Actually, go ahead and buy a whole bunch of cords of different lengths. Just having a few lying around where you use them—one at your desk at the office, one or two in your backpack, maybe one in a jacket pocket—makes the actual act of plugging in your headphones and listening to them so much more pleasant. It sublimates your cans from a utilitarian piece of stock gear to a custom-fitted little piece of joy. If that sounds extreme—maybe it's extreme—think about how much you like well-tailored clothes or a perfectly fitted chair. Oh, this length of cord is fitted almost exactly from the side of my head to my hip pocket. Things that fit you perfectly are wonderful, especially ones you've picked out to replace something cumbersome and idiotic.
Somehow, not all headphones, even expensive ones, have a detachable cord on the cups. Many just force you to live and die (and die and die and die) with the cord they come with. That sucks, not just because you can't switch out lengths—like say, a longer cord for your armchair at home, or a medium-sized cord for your desk—but because the male end that ends up in your pocket is the most common point of failure in headphones (though DIY fixable with a solder gun and a £2 new jack). So probably keep that in mind when picking out your next pair of headphones.
Life is more or less a droll succession of inconveniences, which often as not you just deal with and walk headlong into, like a front lawn full of rakes. It's worth the 10 quid or so to make this very simple thing that you use every day that much more enjoyable.