This is a guy thing as far as I know. But picture this, and I'm sure many guys out there have experienced this one:
You're wearing office attire: pressed khaki's, button up shirt, tucked in and neat, some sort of brown-ish loafer or hush-puppy style shoes, and possibly matching dark socks of some kind. You've been running from meeting to meeting and drinking tea or water or coffee (or all three) and now you get your first break and head directly to the nearest restroom. You lock-in on the target and race to the closest available urinal and unzip your fly. Then you do that stupid clumsy move with the thumb where you try to slide your shirt tail up so you can get hold of the elastic waistband of your underwear to pull downward to let Mr. Happy out - so you can play super-soaker or Tom Clancy (on those imaginary terrorists hiding in the back of the porcelain fortress).
But the problem is your thumb can't seem to get the shirt out of the way and you can't get to the elastic waistband fast enough. The bomb is ticking. The music is getting louder. Sweat beads are forming on your forehead. It's like deciding whether to cut the red wire or the blue one. Think fast! Pressure is on! The Bladder Monster is pounding at the door like a DEA squad on a Bronx crackhouse. Suddenly you scream out loud: "get the **** out of my **** **** way!!!", and you cut the red wire and all is good. Now you can relax as your eyes water up from the sensation of letting go.
Shirt tails and elastic wastbands are the work of the devil.