Toni Braxton Goes Off on Tamar's "Negative" Attitude -- "I Can't Take It Anymore!"

In a sneak peek at tonight's season finale of "Braxton Family Values," tensions boil over during what should be a fun slumber party between mother and daughters at Toni Braxton's home.

"We've been having a really great day talking about what it's been like to work with each other while filming the show," Toni says in the video confessional, setting the scene. "Unfortunately there's some negative energy and I don't want this day to go off the rails right now."

We then see Braxton playing cards with sisters Tamar, Towanda, Traci, Trina and mom Evelyn ... a game that takes a turn for the worse when Tamar starts talking about how the show has changed each of their lives.

When her siblings dismiss her opinion, Tamar gets ticked ... but it's Toni who really loses it when Tamar voices herfrustrations.

"I'm done. I can't do it anymore," says Toni, storming out of the room. "It's too much. This attitude about everything. I can't work under these conditions!"

"I can't take it anymore. We can't ever seem to just have fun without getting emotional all the time," she adds in a private moment. "I wish Tamar would stop it. She's my sister, I love her, but we're just always arguing all the time. She's the ringleader, but she doesn't see it, she doesn't see herself."

The game falls to pieces even more when Tamar then gets up and leaves the room ... with mom Evelyn following after her, absolutely furious.