I first started editing on 29 May 2003 (on a dynamic university IP), when most articles were a few unreferenced lines, and most links were red. I was pulled in because I enjoyed adding content and seeing the links turn blue. There were only about 800 active editors on English WP. I remember when it hit mind-boggling 200.000 articles, and I doubted it would get much bigger. I got an account in January 2004 and soon became an admin, due to my prolific article writing and troll-fighting. But I got extremely tired of the trolls (there were more of them back then) and left late 2005.
I could not stay away so in 2006 I started this account and in 2008, I was again made an admin. Wikipedia has changed a lot during these years. In spite of the larger population of trolls back in 2005, I miss how much smaller it was and in retrospect the atmosphere was more relaxed, and ... convivial. Wikipedia has grown bigger than I could ever have imagined, and so important, but we have lost things in the process. Still, I am very fond of Wikipedia, and although I may not log in for long periods, not a day has passed without me browsing it.