How to be Insulting in Church: Arrive late for any service and arrive noisily. Forget at least one, if not both books, and try to make others stand up while you go back for the ones you need.
How to be Insulting in Banks: Put your old sandwiches into the night safe pouch and complain by letter when it's returned to you empty.
How to be Insulting in Church: Always try to be half a line ahead of the vicar, and always be as loud as you dare in the responses.
How to be Insulting Abroad: Insist on paying for everything in sterling.