Why does Lady Catherine not want Darcy to marry Elizabeth?

Where to start with this question?!

Lady Catherine thinks Elizabeth is a poor match because: 

Elizabeth comes from a family with little wealth and no connections.
Her sister, Lydia elopes with Mr. Wickham 
Elizabeth is very opinionated and outspoken
She does not stand out in any of her accomplishments

There is very little to recommend a match between the two in the eyes of Lady Catherine.