I have to agree with Ethel here, it is a form of bullying. I used to have a 'friend' like this, but she used to put me down to my face infront of other people, knowing I wouldn't stand up for myself, coz I dont like to cause a scene.
When I eventually told her she was being nasty she would say she was only joking and where was my sense of humour, even though she knew she was being a biatch.
I let our 'friendship' fizzle out in the end and I dont miss her at all!!