I'm exactly the guy Wikipedia tags with the conservation status of "least concern": a middle-aged, white male from a G7 economy with a long career in a STEM profession.
I was fairly active during the Wikipedia heyday 2005–2008, but eventually I realized that my motivation was only 75% encyclopaedic, so I wasn't ultimately a very good editor.
I find it particularly difficult to cope with the situation where a certain fact or perspective is considered common knowledge among insiders to the degree that no one important can be bothered to write it down, because everyone with a clue already knows. This is somewhat parallel to how rarely psychology experiments are successfully replicated. There's more in it to publish a novel result, than to confirm—or worse, fail to confirm—a dubious result with a solid p-score etched into a giant grain of salt.
These days I mainly jump in to fix something glaring on an unpopular page that hasn't seen much love for a long time, when my peregrinations take me into the stagnant backwaters.
I run my own instance of MediaWiki for personal notetaking, which I use extensively. I'm extremely proficient with wiki syntax (to the degree that I've modified my Linux ~/.XCompose to emit a ==See also==\n\n block when I type CapsLock-s-a). I haven't bothered with any Lua templates yet, but they pose no barrier whatsoever. I'll probably dive in when next I upgrade my own installation.
These days, here on Wikipedia, I don't generally return to the scene of my crime, nor do I maintain a watch list to track the fate of my alterations, but I do tend to write more explicit commit comments (in article namespace) than many editors. — MaxEnt 00:59, 24 April 2014 (UTC)