I'll comment about this one.
This summer, I took 9 scouts for week long backpacking trip. The first night we found a campsite near a lake. We made so much noise setting up that we got a visit from a ranger. He told us that our site was the proper distance for camping but not for fire. Since we weren't planning a fire that night, no problem. I told him the next night we would like a fire. So, he showed me on the map were some good fire spots were next to the lake we planned to camp the next day. He also showed us a great spring to fill up water. And, he spent a good amount of time teaching the boys about bear safety and proper food storage. Sure, I taught them that stuff, but sometimes it means more coming from "authority". He even came over the next morning to check up on us and wish us well for the next day. I thought that was the end of him. But, when we were close to the end of our hike the 2 day, I see him at a trail junction. He told me that a VERY large group was camped where we were heading, and asked if I still wanted to go there, or go to a "secret" place he knew of. Then he escorted us to the best campsite we had the whole week.
Now, that is service.