reißverschluß

Can anyone explain to me why some men grunt, groan, wheeze, or sigh profusely while urinating? A few minutes ago, the guy in the next urinal stall was grunting as he urinated. I wanted to ask him if he has seen a doctor for this problem, cuz it sounds like he is putting a lot of effort into something that ought to be a fairly easy activity.

Now that I think about it, maybe I don't want to know.