In the late 18th century, it was common to get annoyed with passers-by. Too much courtesy can indeed be a bad thing - these people were told to 'get behind the fucking velvet' and were soon sold into a life of indentured servitude in Australia. Few if any of these unwittingly courteous slaves survived to be recorded in the annals of history.
"Look mate, if you say thank you one more fucking time I'll tell you to get behind the velvet"
- Connor in AC3
"Shut the fuck up and take another sip or just get behind the fucking velvet already."