The border collie shepherd was the best mixed breed I ever had. The shepherd makes them smart and protective, the collie makes them good family dogs. I can explain with a story. My brother Paul told my neighbor he could borrow his stereo. Smoky knew this neighbor, he petted her all the time. He came over and she allowed him to enter but when he tried to leave with that stereo, she growled and blocked him from doing so. He had to call my brother who had to come over and remove the stereo himself giving it to his friend in front of Smoky, only then did she let him take it.
I also have a story, The Tale of two Burglary's in the story section of the writers guild here:
The Tale of Two Burglars