I can't stand noisy bikes. The sound of brake pads rattling, a chain slapping, or housing knocking around inside a frame gets under my skin, and I can't rest until I've found the cause and a solution. Based on the number of aftermarket chainslap-silencing solutions, and the measures taken to quiet the bikes seen on the World Cup DH and EWS race circuits, I'm definitely not the only one.
My ideal bike is one that's almost completely silent, allowing me to focus on the trail ahead instead of trying to diagnose that intermittent 'tick, tick' sound that's coming from some mysterious place. I even prefer quiet hubs to ones that sound like I'm being chased by a bunch of murder hornets. Sure, some people see that as a way to alert others that you're coming, but that's what my voice is for, and if I regularly rode in a spot with lots of hikers I'd buy a little bell.
These days, achieving a relatively quiet bike is a whole lot easier than it was in the past. Back in the days of rear derailleurs without clutches, multiple chainrings, and chainstay protectors that didn't really do much, it was a lot harder to muffle all that racket. I used to wire a piece of elastomer to my derailleur body to make it stop banging into my frame, and used old downhill tubes and electrical tape wrapped around the chainstay to quiet things even further. My boss at the bike shop I was working at back then was very, very frugal, and flew into a rage when he realized that the electrical tape supply had been greatly reduced by us shop rats making our own chainstay protectors... Ah, the good old days. My big ears don't like noisy bikes, but where do you fall on the scale? Can you tolerate some knocks and rattles as long as your bike is working properly, or will only the sound of silence make you happy?