So Equire was running a big marathon of PandR and I happened to turn it on when the two part finale started. After the finale was over the next episode was the pilot. It has been a while since I had seen it so as I was watching I realized something. After seeing pretty much the same cast of characters for a few seasons towards the end, it can be easy to forget characters then had left. One of those was, in my opinion, the single most important character to the story line of the show and allowing us to have the six amazing seasons of great memories from this amazing cast. Without the quiet city planner, Mark Brendanawicz, who sat across the courtyard from Leslie, none of this would have been possible. In the series opening episode, Leslie finds out that there is a large pit in an abandoned lot during a open forum. After promising the complainant to fill the hole AND build a park, Leslie begs Ron to allow her to build a committee to attempt to fulfill her promises to Ann. While Ron is thinking about his answer, Leslie goes to Mark for help. After talking with Leslie, Mark decides to cash in a favor with Ron in order to get Leslie the lot. Although he was on the show for two seasons, it's crazy to think that the single person who made the whole show possible was never seen, heard from or even mentioned again.

TL:DR In the pilot, Leslie wants the abandoned lot and Ron is saying no. Mark Brendanawicz cashes in a favor with Ron to get her the lot. No favor, no lot for Leslie, no show.