I compliment people's old bikes. I've only gotten a few comments- and only once has someone actually known what I was riding and I glowed about that for a week.

Although it wasn't an old bike- I was trucking along and this couple passed me- I saw and recognized the bike and said something to the effect of cool bike- and then I recognized the rider. The bike was an Ellis Strada Fango and the rider was Dave Wages. That was pretty cool.