When I first started playing I thought that I could use the red glove on the cat to make him stop scratching the couch
I thought that when the tutorial said "they're trying to make a baby, they will have privacy" I was supposed to close the game, which I did... surprise, no baby
I worried that if I punished a mother with a baby, the baby would be punished too, so I never punished a mother with a baby... i still don't :P
I thought that it was weird when they were "admiring the magic fish" when they had no fishtank XD (it turned out to be a painting)