I dunno about shirts, but I'm annoyed by the recent surge of words-across-the-ass shorts. It's an even worse trap than the words-across-the-tits shirts
Also, I'm not typically Mr. Social Conservative, but even I feel a bit of concern when I see an 8 year old girl sporting a pair of shorts with "bad girl" across the ass, all apparently with father's blessing (since he was right there).
I remember a couple years ago when I was at the mall, confused by a bunch of mallcore lookin youngins' sporting Iron Maiden shirts. I was unsure what to make of it until my then-g/f explained that it was related to the song "Teenage Dirtbag" and whatever band was behind it. I never really looked into that, and now I'm curious, in retrospect.