I get what you mean about it being a weird kind of happy! I've got a war story that I really enjoy sitting down and writing, even though it's kind of a horrible topic. I'm super-interested in researching war and stuff though, so I guess maybe it stems from writing about something I'm really interested in? I don't know, it's cool. But yes, writing makes me happy when I'm really into it. It's a cool feeling.
That makes total sense! I get ridiculously geeky when it comes to researching war and politics.