impeccably ill-mannered
The quality of knowing how to offend and alienate as many people, in as short a time, as possible.
He was their new neighbor, so comprehensively offensive to everybody that within a couple of weeks of his arrival he was a laughing stock. No one wanted him there. No one was speaking to him, or ever would. He had trained hard to become what he was - impeccably ill-mannered. It was a talent given to few.