A while back a friend of mine asked me if a hotdog was a sandwich. And my answer was yes, and that to me, "anything is a sandwich as long as I don't have to eat it with a fork or knife because then it's a stir fry".
I think this really gets into the mystery of mechanics for me. It doesn't really matter what a mechanic is as long as the thing that I'm doing results in fun. But, you could take the hotdog statement both ways, and really that is what is so fascinating about it. How do you organize the way you have fun?
As a kid, (and later of course) I remember walking back and forth in Final Fantasy (or any number of RPGs) for HOURS and HOURS and somehow I just had a blast. Now with a 4 year old, I was trying to explain Terraforming Mars and I was floored at what I considered super satisfying and fun. Moving cubes around.
In general, I really enjoy manipulating things (area control, player interaction), building/constructing things (engines, puzzles), making good or effective decisions (deck builders, worker placement) and taking risks (dice rolling, auctioning, card draw). As long as an action isn't really bulky and annoying (Settlers of Catan trading, hording cards in Ticket to Ride, etc), it doesn't matter as long as those boxes get checked.
Especially with this flood of board games, I feel like having a better understanding of what is core to our concept of fun is more important than just the categorization of mechanisms.