Pros
I got to enjoy the architecture of DC; the outsides and insides of some very interesting buildings. Some had multimillion dollar lobbies, statues, incredible elevators, etc. The challenge of finding parking and getting in and out of buildings quickly was kind of fun. I met some nice people and they appreciated my work as far as getting their delivery done quickly. I also enjoyed the frequent parallel parking (yeah, I'm a little crazy) but it's a good skill to have and it's awesome when you nail it on the first try.
Cons
Extremely low pay, risky to be driving/parking/driving/parking all day in DC; one flat tire or parking ticket or busted headlight would negate your entire day or even a week's pay. The worst was waiting for the next call which sometimes took a while and sitting in traffic every day, all day, then they would send me in the wrong direction for my last delivery so that when it was completed I'd have a 90 minute drive home in the worst traffic of the day.