See My Team Jersey

I dunno, Gary, but I will give you another one.

Now this phenomenon is peculiar to California, I think. Men, some of the in their thirties and forties, buy a brand new full-size Ford, Chevy or Dodge pickup...extended cab or crew cab. And then they spend a lot of money screwing it up...putting HUGE tires on it and jacking it up a foot or more. The tires are "knobbies"...off-road treads that howl when the truck is doing anything over about 20 mph. The jacked-up vehicle handles horribly, and the high center-of-gravity makes rollover accidents much more likely. The big tires add rolling friction and wind resistance. The driveshaft U-joints have to accomodate a severe angle, shortening their life to a few thousand miles. So...a perfectly good truck is turned into an unsafe, ill-handling, inefficient, noisy abomination. And it costs a LOT of money to do this!
But here's the thing that makes it absolutely insane, if anything further is needed: The front bumper ends up at just about the head-level of a person driving a normal vehicle, so in a T-bone accident, it is likely that the driver or front-seat passenger would be decapitated.
I have read that this is illegal. Front bumper height cannot exceed a certain value. But there are thousands of these abominations lurching about the roads of Southern California, and I have never seen the cops do anything about it.
To repeat your question: Why do they do that? I guess it's some macho thing. Whenever I see one, I think that the driver should be home playing with his Tonkas in the sandbox.

I would be willing to bet that those men get a lot of those shirts as gifts. I have a 30 year old son, and I can imagine giving him a Red Sox shirt. So I guess they wear what they have.

Nancy- I was going to mention that too. I have a Arizona Cardinals jersey I got as a gift, and used to wear it to football games when I had season tickets. However, rather than just let it hang in the closet forever, I have worn it when out and about before. I don't see anything wrong with supporting a favorite team of someones. Macho doesn't have anything to do with it, never did for me anyhow.
So I think the message is "Go Suns".

You got me Bert. I've seen those things in Phoenix as well. At least some of them here actually do go off road

I few of them may go off-road, Gary, but I bet the vast majority of them never get off the pavement. There's no accounting for actions caused by excessive testoserone. The jerseys may have a similar motivation..."HEY, LOOKIT ME!!! I'M STILL A YOUNG STUD!!!"...denial of approaching middle age...dunno.
Or maybe as John says, hey, I got this shirt hangin' in my closet...

The motivation behind fashion is an interesting science.

I cannot figure out why some people have to make a big deal out of nothing? Gary does it really bother you about someone wearing a sports jersey, see a psyc

Scott:
I don't think I ever said it bothered me. I said I don't understand the reasons why guys do it, and the only ones I can think of seem rather silly. And it wasn't me that made a big deal out of it - the professional sports leagues make LOTS of money out of it.

Maybe its just part of men's fashion motivation - as Lisa stated - just as halter tops for women (some who shouldn't wear them). Or perhaps as Bert stated its just a way of ignoring the obvious - you are a grown-up, presumably responsible man. Or it could be just a way to have fun in an otherwise serious world?! Perhaps they went shopping at Valu-Village or Goodwill and those were the cheap shirts!!!