The reality of most drivers today ends at the inside surface of their windshield. Most Americans have little or no spatial awareness. Sad but true. When someone parks their shopping cart blocking the aisle I just say "Excuse me" to get their attention. If that fails I'll move their cart out of the way saying with a smile "I'll just help you move your cart out of the aisle." If that causes them to become indignant then ITS ON and they ain't gonna' like the verbal shellacking that comes next. I try to be diplomatic but I don't suffer fools easily.
I'm sorry to say that unless it's an older or disabled person I just come unglued and get every bit as rude as they are being. And to those that cant see past their nose, I have the train horn on my truck. One blast and I've seen people drop cell phones and lipstick, eyeliner newspapers...
I scared one dude so badly he jumped in his seat and I watched as his cellphone went under his tire.
I think he had to go clean himself.
Now one of the Grey Guardians.