@ mrmerlot: Wikipedia editors are required by policy to assume good faith (see http://en.wikipedia.org/wiki/Wikipedia:Assume_good_faith), meaning they should assume you were trying to help and just got it wrong if you made an edit that did not improve an article. If this was not your experience then you have a legitimate grievance. Don't let that sour the whole project for you, there is still plenty of good work to be done. ;-)
Alternatively, you can find a specialist wiki on a subject that interests you to contribute to instead. For example, The Simpsons wiki (http://simpsons.wikia.com/wiki/The_Simpsons) or the Star Wars wiki, Wookieepedia (http://starwars.wikia.com/wiki/Main_Page).
Wow, wish I had saved/screenshot the page ... someone for a short while HAD edited Wikipedia, claiming Joe Cassano was a trapped bolus of excrement in a Crohn's patient gut, complete with references of other bowel movements that went on to change human history (More Crap! episode of South Park , http://www.southparkstudios.com/guide/1109/). It's been changed back to its original boring entry.