I love copy-editing and always have. Unfortunately, by the time I became an adult most papers had fired their copy-editing staff. Most of the time, I edit because I'm reading an article and find an error or a unsourced assertion. I also enjoy finding references for articles, and reading the Administrators Noticeboard to learn what not to do.
I've just started the The Wikipedia Adventure, even though I've been editing here since day one. Wikipedia has changed a lot over the years, for the better, and I think one can always learn something new, which is why I've used Wikipedia almost daily since 2005.