Looking for this movie. I only remember the beginning. A man forgets his anniversary and hurries to the shop to get something. But a stray dog knocks over a display and the shop owner blames the man. So he goes home empty handed, thinkng about how he's gonna explain to his wife/girlfriend about it. But the dog follows him home, and the lady thinks that the guy got her the dog and is estatic. His mother in law is less impressed and expresses how small the dog is. I think there is a note tied to the dog's collar, and it's some sort of romance/comedy/crime sort of movie. It's an old one thought, maybe 60's or 70's. Thanks!