1. Disco!!!!
Prior to the late '90's pop explosion, disco was the most annoying type of music. Mostly about "style over substance" like the lack of depth & mostly tie in with dances. Also invented to have business at roller rinks & clubs.
2. teen idols
I know that teen idols were around long before the '70's, but the '70's had the cheesiest bubblegum acts that would make N' Sync look cool. With the only exception of the Jackson Five. The 5 worst offenders: The Osmonds, David Cassidy, Bay City Rollers, Leif Garret, & Andy Gibbs. Unlike The Beatles, they had lacked talent & are looked as a joke. Thankfully the '80's were a better decade with teen idols that had talent along with their image like Duran Duran, Madonna (before 1991), George Micheal, Bon Jovi, New Edition, & Debbie Gibson.
3. Cartoons (some, not all)
Most of the cartoons from the '70's were mostly "Scooby Doo" rip offs & teenagers with bands. Don't get me wrong, some of the 'toons were good/ok like "Josie & Th Pussycats" & "Hong Kong Phooey".
But some were just plain horrific like these examples: "Goober & The Ghost Chasers", "Laff-a-Lympics", "Pebbles & Bamm Bamm", "Funky Phantom", and "Devlin".
4. variety show overload
The second most embarassing tv trend in history, next to reality shows, with about every celebrity from the Jackson Five, Sonny & Cher, to the cast of "The Brady Bunch" (except for Eve Plumb, "Jan Brady") had a variety show. Enough said.
5. James Taylor
So bland that he makes John Mayer sound interesting. IMO, he's the most boring singer/songwriter of all time with dull songs like "Fire & Rain".
6. Journey
Even '70's rock had it's share of cheese like Journey, fronted by Steve Perry who sounds like if he's muzzled. Unfortunately, their popularity lasted 'til the mid 1980's. Along with bad music videos that would rank amongst a "worst" list.
7. Pet Rocks
I just don't get it? I was given a "used pet rock" in the late '90's as a gag gift & the only good use of it is for a paper weight.
8. MASH
IMO, one of the most overrated tv show of all time. I've heard that it was a comedy, but it had to be one of the most boring shows of all time.
9. The Waltons & Little House on the Prarie
See "MASH", but I don't think they're considered a "classic"
10. polyester
IMO, the most uncomfortable fabric of all time. Not because they looked tacky (I know that the fashion was popular), it's because it makes some people feel itchy like a woolen sweater worn at a sunny day.
11. Grease
Not because I don't like musicals, it's because it's the most cheesiest movie of all time. Some dishonorable mentions: "Rocky Horror Picture Show", "Love Story", "Beyond the Posiedion Adventure", & "Night of the Lepus".
12. Farrah Fawcett
Overrated.