Sheldon has never been particularly nice to Howard. He likes to rub in Howard's professional career and lack of doctorate. A trip to space wasn't even enough to stop Sheldon's ribbing.

On Thursday, Howard decides to try and strengthen their friendship by inviting Sheldon to Houston with him, but it goes bad. Very bad. Very, very, very bad.

Insults fly and the divide widens. Bernadette tries to bridge the gap and bring them back together again on The Big Bang Theory season 7 episode 17.

While that's going on, Raj ask Amy for help writing a letter to a woman. The best choice? Maybe not, but maybe.... Raj needs any help he can get to find the right woman for him.

Also, Penny is offered an embarrassing movie role. Will she take it? It's an acting job after all.

Check out the official photos from "The Friendship Turbulence" below: