(great thread)
I learned at least something from the few truly bad components I ever owned. But the first was the worst (and the most learning): it was an Infinity floorstanding 3-way with ribbon tweeter, 3" midrange and 10" woofer in a tall, shallow tilt-back cabinet with wood endcaps. To my not-yet-experienced-audiophile eyes, these speakers looked amazing. And I was reading about giant Infinity IRS speakers that cost as much as small houses of the day, so plunged on these "gently used" speakers. Think I paid $1,200 for them.
The sound was AWFUL. To this day it’s easily the brightest, edgiest sound ever. At least some blame went to the ribbon tweeter. But even the woofer sounded awful. It was made of translucent polypropylene which was pretty, but it had a weird "trampoline" (bouncy) bass sound that made me never want polypropylene anything again.
To make it sound better, I changed everything upstream that could be changed--the sound never improved. I finally realized speakers are one component where the "neighborhood" rule is in play: if you don’t get a sound that’s at least "in the neighborhood" for you from the get-go, you’ll never mod, reposition, or otherwise refine those sound-like-ass speakers.