How to be Insulting in Banks: Try to use one of the automatic cash dispensers, but use it incorrectly. If it's inside the bank, do this until someone is sent to help you out, or until you're asked to leave. If it's outside the bank, kick the machine and try to open it with your car keys, a penknife or your umbrella.
How to be Insulting on the Beach: Buy several large newspapers, and leave these lying around so that they blow all over the beach.
How to be Insulting in Hotels: If you have to get up early, do it with the maximum amount of noise. Run a bath loudly and sing in it.
How to be Insulting at Christmas: Buy crackers without any little gifts inside. If you have the time beforehand, put unpleasant little remarks and observations inside them instead. You might try to glue the paper hats together so that they tear when the guests try to open them.
How to be Insulting at Christmas: Turn up the television when the carol singers arrive and turn off the lights until they go away.