Maybe people I?m A Grumpy Old Man It?s Okay If You Don?t Like Me Not Everyone Has Good Taste Shirt . Who say this really underestimate how difficult it is to train certain breeds. My border collie was completely potty-trained and had learned several tricks in the first few weeks of when we got him. (We got him when he was a couple months old.) Soon afterward, we got a chihuahua and she was also just a couple months old at the time. This dog is so much goddamn harder to train. It took nearly a year for her to even be potty-trained. Part of the difficulty is how stubborn they are. Part of it is that they?re so fucking stupid.