Because of disco, many refer to the 70's as the worst decade for music. I have to disagree. In the '70's, you had funk, jazz fusion, rock took a new, interesting direction with bands like the Eagles, Fleetwood Mac, Chicago, etc. It was in the 70's psychedelic rock really started to develop with bands like Pink Floyd, Steppenwolf and Iron Butterfly. Even prog-rock had a few good bands; lot of people would put him in the experimental rock category, but Frank Zappa comes to mind.
I would have to say the worst decade for music are the 80's. Especially the early-80's: The soul was completely sucked out of jazz fusion and funk long ago. Rock bands' egos, along with drugs, started getting in the way of their creativity, which paved the way for glam bands. And with this example, you have songs with that remaining layer of disco, combined with the newly found synth instruments.
I remember as kid in the mid-80's, sitting in a dentist's waiting room hearing crap like this. The early to mid-80's was a period in time doctor and dentist offices moved away from Muzak to contemporary easy listening. I was only around five, so I haven't yet formed my own taste in music, but knew that wasn't it. I feel for the poor souls who had to experience their teenage years in that time of our history. People in the 40's have my sincere respect.