OMG, I played Nintendogs too. I still have it actually. Once, my sister told me that the dog I had created on her save file "ran away". more like it went to an all exclusive spa day at the dog hotel. Long story short, it never came back and i'm still trying to be okay with that :'(
Side note: i'm not actually still upset about the dog, that was a joke. My humour is quite strange tbh (and a lil self depreciating)