As much as I (and my fitness) enjoy riding bikes, I also take deep satisfaction from a soundless, smooth shifting, perfectlty adjusted bikes. All mine are constantly monitered and thus hardly ever get out of true. But, as for the bikes our tenants and my wifes guests (or anyone riding by going sqqquuuueeeccckkkkkkkk! for that matter) I really just want to fix them. In fact, I just did. I noticed one of the women from my wifes prayer group had parked her bike in our garage. So I check it out. Old BSO rusted and badly adjusted. So I put the saddle on the right angle, lubricate the drive train (I was doing that on my commuter so I had the oil with me) and notice that the drum brake is too loose. I adjust that right up, check the derailer and see that the cable isn't even close to being right get that right, so I get it shifting nice and smooth.... AND ITS NOT EVEN MY BIKE!
Yikes, I think I'm a bike fixoholic. But it is so satisfying when it works the way its supposed to.