I think calling a post "common courtesy" and then describing the lack thereof of a person is itself laying into him.

That said, if you want specific examples:

"How can people be so rude these days?" .

and

"I can't be the only one out there that gets so peeved over idiots with no manners am I? "

When you finish with that, you are laying into him for everything on the laundry list..the line, the feet and his accurately measured (somehow) briefcase.