Why downtown?

Walkscore is an interesting google map wiki. Type in your address and it gives you a walkability score from 1 to 100 with 100 being the most desirable. They say 90 to 100 is a walkers paradise. I scored a 97 downtown, which I already knew from the fact that I can go weeks without seeing my car.
Walkscore runs down the whole list of reasons you should walk instead of drive, but they miss the most important reason of all as far as I'm concerned, socialbility. Do you drive past people you recognize and wave? I walk by and stop and talk, its hard to go more than a block or two downtown and aviod this from happening.