Whereas most posts have an obligatory xkcd, I feel like this one deserves a Dark Legacy Comic:
I spent 6 years raiding pretty much every night with a guild that was always ranked either number 1 or 2 on our server, and the highs (and lows!) of that time were completely different from any other game I've ever played, before or since. I miss the feeling of some of those epic kills, but I don't miss the grind, or the arguments on teamspeak when we'd had a bad night's raiding. Also everyone I used to be guilded with has become disillusioned and quit (with a few serial relapsers!) so it just wouldn't be the same if I went back to it, even though every new expansion release does make me think about re-subbing. So it was a very good experience for me, and yes I'd definitely call it a good game when I played.