When I was but a lad, and we lived in France, they built a youth center across the street from the front gate of the housing area. They had ping pong tables. For anyone who thinks there probably was no life before video games, well, ping pong was it. Well, that and smooching.
Anyway, I learned a very interesting lesson in life that I have never forgotten. When I played ping pong with someone better than I was, I played better. A lot better. When I played with someone who was not as good as I was, I played worse. Not a lot worse, but I got sloppy.
I've seen this put another way, which is more clever than I could come up with: It's Harder to Soar With Eagles When You Work With Turkeys.