We used to have dobermans. We had one called Shadow and my DH taught her how to smile!! So when salesmen came to the door DH would call Shadow to the door before he opened it and then he would tell her to "Smile". They couldn't leave fast enough and they never came back! LOL
Of course what they didn't know was if she was outside when someone pulled into our drive she was the first one to our door whimpering to get inside to hide! LOL