These were things that were all the rage when I was a teenager. (I haven't even mentioned disco music, streaking, CB Radios, Pet Rocks, T&A television shows, platform shoes, punk rock, and even more of that et cetera!)
So here are my predictions for my daughter's teen years, circa 2020:
High Fashion Amputations. Sorry, losers! Tattoos are now removable. Piercings and ritual scarring just aren't permanent enough. The callow youth of the future will insist upon actually amputating parts of their bodies. "But, Da-a-a-a-d! (Insert name of future bad role model media star here) cut off her whole left hand! I just want to nip my pinkie finger off at the second knuckle. That way I can get some of that super-hot stump bling that all my girlfriends are wearing! I hate you! I hate you! I hate you!!! You're the worst Father ever!!!"
IV Party Bags. Yep. That old-fashioned "beer bong" just didn't get you drunk enough, fast enough. And don't get me started on those clumsy, inefficient, lip-burning crack pipes. The smart substance abuser of the future will wheel around those hospital IV coat-rack-thingies with a catheter permanently stuck into his or her arm.
Pop Music. Well, forget about it! There is no way to predict this, history has shown us that much. Will there be a strong reaction to decades of "gangsta rap" that yields gentle, articulate songs about being polite to one another? Will there be a further degradation wherein the hit parade will consist of sound files constructed from individual words sampled from "old skool" raps? Will people be inserting audio-frequency-activated pneumatic jack-hammers into their ears because there just isn't any way to make 18" bass speakers louder than they are now? Will people only listen to music if it is available as a cranial-implant cell phone ring tone? The magic eight ball is mum on this one, folks!