Something had really been bothering me about men's dress pants lately. I couldn't figure it out until we went to our biweekly after work hang out and people watched. It's the pockets. The pockets on some flat front pants are cut on an angle. If the pants don't fit properly they bulge out at the crotch and the pockets puff out - moving the eye horizontally across the midsection - and not in a good way.
Solution - look for pants that have pockets that are cut vertically.