It's not just the clean, well-lighted place that does wonders for the postal patron. Nor is it the availability of packing materials, a scale to weigh your own packet to avoid lines, a worktable right where it's needed in the central waiting area, 1,300 rental mailboxes, the clearly labeled slots for outgoing mail, a counter for retail sales and a separate counter for more complicated transactions. It's not its easy access right on Kirkwood Road or the Starbucks a couple dozen steps down the strip for that necessary caffeine lift on really crowded days when you feel the crush of the four million pieces of mail that move through here in an average four-week cycle. Nope. Above and beyond all of this, it's the staff -- eager to help, efficient, cooperative, able to answer multiple questions, suggest options and smile. In its fantastic facility, the Kirkwood post office presents a model for any business: Take great care of your customers.