Most of the bands named in this thread are nowhere near worst rock band ever. Sure, they may not be your cup of tea but that doesn't mean they don't have talent and haven't realized some of it. For example, I'm not fan of Rush, but that doesn't mean they are the worst band ever. Just not my style. There is no denying they've got talent.
The '80s LA glam scene sure led to some of the most superficial music ever, but those guys could actually play and sing and write some catchy tunes. I'd say music of the last 15 years has been some of the worst ever. These pop/punk bands over the last five or ten years, that all sound the same, and some of the so-called alternative genre that was popular in the mid 90s...alternative to what? Good sounding music I guess.
Want to blend punk and hard rock, with pop sensibilities and do it right? That's GN'R. A pity what happened to that band, though all those guys are still rocking hard to this day. Saw Axl's (no e) band twice earlier this year, he's moving and singing like he did back in the day. Pretty remarkable considering he's almost 50!