Honestly, the only real inappropriate time I played Animal Crossing was when I was in Meijirs. Meijirs is a sort of superstore, it has groceries, clothes, games, toys, and other things.
I was keeping my dad company while he works, he patrols around for snow, and then tells his boss if places need snow plowing or salt. He dropped me off at a nearby Meijirs so he could go clock out (I'm not allowed to go with him to work, but he lets me go with him sometimes anyways.). Anyways, I walked around the superstore for about an hour, before sitting down next to one of those claw machine games and opened my 3DS (I usually take it with me on sleep mode so I can get streetpass. Doesn't work too often x_x) and played Animal Crossing.
The workers there kept staring at me funny. Don't know why.
I play during class. Also when I have papers due the next day and should be working on them... who needs an education when you can run a town in Animal Crossing?
Not time, but place. Usually on the toilet. Hey, you're sitting there, nothing else to do, why not pull your game out, and do some playing? I've been doing that since 1989 with Game Boy, it's amazing how much you can get done when you're waiting in line, on the toilet, etc.
I dunno if it can be classified as inappropriate, but I've been playing pretty much every waking moment recently. I get tunnel vision when I set a goal for myself and I want it done as soon as humanly possible; right now I'm trying to finish decorating the interior of my house so I can move on to landscaping outside, and my partner has gone out for full shifts at work and come home and been like "You were sitting in that exact same spot when I left. Have you been playing New Leaf this entire time?"
I think I've beaten me playing it at Meijirs post from earlier.
I played Animal Crossing while in the ER. My dad was there and the doc took him to get x-rays. When they left, I pulled out my game to play Animal Crossing. I had one earbud out because it was funny listening to the couple next to our block talk about their friends and such.