Who is Aunt Agatha from Life with Jeeves and what is their importance?

Berties, Aunt Agatha, is married to Sir Spenser Gregson. The couple owns a country estate at Woolham Chertsey, Hertfordshire. Bertie occasionally refers to Aunt Agatha as "the family curse". He views her with fear and trepidation, and she views him as a vapid and frivolous wastrel. She does, however, have aspirations for her nephew, something made evident through her attempts to arrange his marriage and find him a good position.