Perhaps "too good" is not quite the right phrase, but more, "not quite matching the intended use". I modify my bikes to suit my own use - leather saddle, retro LED lights, new saddle bag, new brake pads, replace cables as needed, new tires, etc. I make concessions to getting the bike on the road and into a safe and ride-ready state. I've sold a couple bikes that were basically mint and original down to the perishable parts because I thought it inappropriate to start modifying for my own use. In those cases, the buyers were people who collected old bikes and wanted a really pristine and original example of something. It was in deference to the originality of the bikes. But these were rare exceptions. Almost all of my bikes are pretty humble riders where it's perfectly OK to change cables or tires, or put in LED lightbulbs, etc.