Ugh, the on-purpose thong string hanging out is soooo trashy! A girl in my English class a few years ago had her thong string hanging out every single day - and not like an accident, like maybe her jeans were a bit more low-cut than she thought. No, her thong string was out on display a good 3 or 4 inches above her jeans, and her shirt all pulled up past her belly button to show it off. One day my friends and I dared a guy to go stick a dollar in her thong string, like a stripper... he did AND he slapped her ass and winked. She was PISSED! But she didn't wear her thongs all hanging out after that. I think we did the rest of the world a favor!
With the guys and boxers thing, it doesn't bug me if it's like just a peek of boxers. But when a good 6 inches is showing and your pants are sagging down to the floor and the crotch of your pants is at your knees... pull those damn pants up or I'll go ahead and pull them down. Another thing that bugs me is when the boxers are on display and thus a viable part of the outfit, but clash horribly with the rest of what the guy is wearing! If you're going to wear a navy and white striped shirt (perfectly acceptable), don't wear red, green, and brown plaid boxers. It's hideous. Ugh it's just so stupid to wear huge pants like that. Though I must say, I'm not wild about guys wearing the supertight girl jeans, either. Can't guys just dress like guys? Jeez.