Well spoken Jacqueline. I think you hit the nail on the head. Teresa is completely ruthless and, worse, completely and utterly unhappy, which is a mean and dangerous combination.
In watching the shows she clearly makes every effort to undermine others - Just listen to her relentless self-promoting, negative off camera comments about cast mates.
Instead of finding one positive about Melissa's baby christening, Teresa shows up late, then off camera criticizes the number of guests and the entire event indicating she could do better than Melissa. Seriously? Teresa can't afford to be generous and allow that someone else might be able to do something well?
I challenge anyone to find more than 5 seconds of unsolicited, genuinely positive comments Teresa has made about her cast mates in the history of the show.
Someone- please pickup this challenge. If there is even one genuinely positive, unsolicited comment about her cast mates I would like to commit it to memory.