Police the behavior of users
Wikipedia is quite big on policing: They police copyright violations, "irrelevant" articles, changes by new users...
The one thing that matters most for the community however, the behavior of users, is left largely unchecked. There are unbelievable idiots and people who don't care about new users' feelings at all, especially among experienced editors and even administrators (even more extreme on the German Wikipedia).
Stop accepting such behavior as if it was god-given. Having a page titled "Don't bite newbies" simply doesn't suffice.
I don't think behaviour should need to be policed. If people are behaving in a "bad" way, it's because something about the environment is leading them to do that - most likely, lots of frustrations. Plenty of online communities function really well without "policing" anyone. Stevage 17:52, 2 December 2009 (UTC)
administrators who have a bad behaviour toward a new user should lose his privileges.Nevinho 19:34, 2 December 2009 (UTC)
This presumes that you can determine what is bad behaviour and what isn't. I propose that figuring that out is the entirety of the problem. And why extend that protection only to new users? Why only extend the enforcement to administrators? The special privileges of admins on WMFs wikis are very narrow and have little to do with the treatment of users. No one should receive bad treatment, new or old users, from admins or anyone else.
Not everyone is a unique and special snowflake. Some people are just jerks. Wikipedia is not psychotherapy: We can't expect the project to cure bad behaviour. I think some aspects of Wikipedia do tend to bring out the worst in people, so you're right that changing the environment can help, but there still needs to be a mechanism to deal with people who are unable to control their own behaviour.
The success of that mechanism, at least on English Wikipedia, is largely determined by how many friends the person has on the projects. Many friends and you are untouchable, few friends and you are cannon fodder. It's only workable because the worst jerks usually have few friends. If fails when the reverse is true. The whole process favours people who invest a lot of time in socializing and politics rather than editing the encyclopedia.