Geez. Judging by all the XLs and XXLs we've either got a lot of the following:
1) A bunch of high-calorie eating, coke chugging at their desks computer geeks
2) Offensive lineman
3) Skinny guys who like to wear shirts 3 times too big for them.
I used to fall into that last category, but finally started wearing shirts that fit my 5'11" now 170 pound frame (i.e., Medium or occasionally Large.) Couple a proper fitting shirt with my building up a hint of muscle over the last 5 or 6 years and it suddenly made me look much stronger and athletic according to my wife and other people.