I used to deliver to a well-known Atlanta tv anchor reporter who had trained German Shepard guard dogs. Her husband was a county police commissioner so these two dogs were his idea. Iron-gated lake mansion with a side door next to the driveway gates. I gave "Chief" a couple of dried-out dog cookies and he instantly became my friend for life. The homeowner got ticked when he saw me do it, he said he would have to have them retrained. His wife just laughed about it. That was about the only time I gave a dog a treat.
Normally I just looked at strange dogs and talked to them in a stern voice, most of them would back off. Dealing with dogs became a sport to me after a while. I ran over some stupid ones that liked to chase cars and I beat a couple across their heads. Some dogs I petted often, I didn't need to be providing treats. I didn't like dogs getting anywhere near my car, some were stupid and get places I couldn't see them.