Just don't screw up and set it to 2003... Your entire village will be overrun with weeds, and you'll get cockroaches in your house.

Yes, it happened to me. I didn't want to wait a day to upgrade my house, so...

"Where have you been? I haven't seen you in.. let's see... 12 months!"

That's really all I use the clock trick for.. skipping ahead a day so something happens.