Hey there, new girl. You just jumped into it, didn't you? The thing about that grudge against your sister-in-law, Teresa, is that it's not healthy for your own marriage to contend with so much verbal venom. Sit down and just have everyone just talk -- no wine, no shots, no fisticuffs -- about why they're so cranky. Learn, grow, move on -- and then have Joe rub lotion on your legs.