It taught me that I don't have to worry about getting injured as long as I bring food with me. : Seriously though, it did teach me a couple of things, such as having a higher tolerance for annoying people and also how to manage finances.
For me it'd have to be something that happened in real life, such as me getting a job with a lot of responsibilities, or even getting into a serious relationship. I can manage most of the changes in-game.
This is exactly the reason why I remain f2p too. I do agree that people shouldn't expect special recognition for achieving a level in f2p, but everyone has their reasons for staying f2p and they should not be talked down to.