I do not know any adult Sarah's, but teenage Sarah's were always a bit of a cow.
Amanda's are made from pure evil, as are Danielle's.
Wendy's, as I have said elsewhere, make me think of damp afternoons and the smell of wet wool, but they are usually friendly and nice.
Female Sam's can be quite sly. Male Sam's are tall and stocky and play rugby.
Clare's are usually nicer than Claire's.
Tracy's like a laugh and a drink and can be counted on to talk a lot at parties.
Carla's will only be friendly when they want something from you.
Kelly's are always friendly.
Heather's are as mad as box of frogs, but usually in a good way.