@collegework, thank you for the wonderful review/recap of your visit. It’s been three years since we made a similar (but shorter) visit, and it was great to relive that experience with you.
Re the dress thing, I think the weather may have been a factor and also it being the end of the semester, when kids are busy AND tired. If you were to attend a football game, however, you would find many students dressed up in a way that you’ve never seen if you’re from the Midwest (or anywhere else!). My son was a tee shirt and jeans kind of guy and he’s started wearing button-down shirts a lot and dressy shorts, along with Sperries (what we used to call “Topsiders”). He also enjoys dressing up and occasionally even wears a tie, so hang onto those Vineyard Vines coupons. Most college kids will need to dress up for all kinds of stuff (interviews, award nights, etc.), so a nice tie can come in handy. (I actually got my son a really cute elephant one from VV, and he loves it. He even loved the bow-tie I got him for his birthday last year.)
I’ll never forget the first time my son said “Yes, m’am” to me non-ironically when he called home. Here I thought he was being a smart-ass, and he was just being polite. While it does seem kind of formal at first, I actually really love it. My son pretty much has just replaced “Yes, please” with “Yes, sir/ma’am.” Manners never go out of style, IMHO. 
Coming from PA (and having many Penn State alumni/students in my neighborhood), I still laugh out loud when I read this: http://www.lehighvalleylive.com/sports/index.ssf/2011/09/why_do_alabama_fans_put_on_for.html
Mind you, plenty of folks will be wearing jerseys and tee shirts at Bama football games, but it wasn’t that long ago (maybe 45 years?), when EVERYBODY dressed up for any sporting event.