The most people-aggressive dog I ever owned was a pure black 75-pound German Shepard Dog bitch I named "Hanna" (for Hanna Reitch, the famed German WWII test pilot). She would not let anyone near my automobile nor in the door of my home unless I permitted it and the lone time that I saw her actually give even the slightest hint of slinking was when she was in heat and a sheriff's deputy friend came over with his 95-pound K9 "Roger" who put her in her place with just a low growl and a bad eye (I'll let you guess the reason he was there but won't admit to anything as, though my deputy friend has been long retired, he could have gotten in a lot of trouble).
Yep. But predictable.