I have the answer! Courtesy of answersaboutmen.blogspot.co.uk/2009/11/why-do-men-take-so-long-in-bathroom.html
"I know what most women may be thinking. "I can poop and be done in less than a minute, so why is he in there for a good hour?" Ladies, you need to understand something; we are men, goddammit. Our diet consists of dead animals, live animals, the blood of our enemies, and beer. Your prissy salad and lady fingers diet shake might hold you for 48 hours, but if I was reading Twilight, staring vapidly into space, and entertaining children, that would satisfy me too. The truth is, we men are out there punching bears, ruling countries, and generally making sure the world runs smoothly for you. So excuse us for taking the hearty shits that are indicative of our superior lifestyle.
A man's shit generally comes into two varieties; the solid turd and the unholy OHGODITBURNS liquid shitstorm. A typical turd is between two and three feet in length and is about as twice as thick as an infant's neck. Contrary to popular (read: women's) belief, the toilet is not clogged because men use too much toilet paper, rather it is because our rigid turds refuse to bend to the will of meager plumbing. Women of course try to remedy this by suggesting that we keep a plunger handy and flush more often. Men of course know that a machete is the only option. The second type of shit mentioned above may be seen as an unfortunate side effect of men's diets, but it is in fact a desirable kind of shit. The typical diet of any man on a given night is grease, hot wings, and beer, and this combination stews up a crock of shit within one's bowels so truly heinous that Cannibal Corpse actually refused to write a song about it. Men actually enjoy having this sort, because it allows him to combine two of his favorite things in life, taking a shit and violence. To a women, the possibility of pooping and suffering a bloody bodily injury seem completely unrelated, but men's colons have rectified this, allowing us to indulge our innermost pooping fantasies as we litter the bowl with what can only be described as the the Tokyo restaurant scene from Kill Bill meets swap.avi.
The other thing that takes a man so long in the bathroom is growing his beard. No, not trimming, not shaping, not shaving. This isn't pubic hair, this is pure, unadulterated facial hair. You see, a beard has always been a symbol of manliness, but few women understand the reason why. You see, one of the basic tenants of manliness has always been the ability to conquer anything and everything that lies in his path. This is why cavemen rode dinosaur mounts, why ivy defies gravity, and why Jesus is afraid to come back. Because we fucking said so. The beard is not actually a part of a man's body, but a separate entity that forms a symbiotic relationship with us, that is, it agrees to grace us with its presence and we agree not to slaughter it with a xyresic blade of folded steel. A man who can't grow a beard or refuses to (ie. a woman) has no control over his environment, and should probably go back to writing "A Ode to my Meat Curtains" or whatever it is that the lesser sex does in their free time."