That's a Bad Twitch!

In You Can't Take it With You Lionel Barrymore's character makes the above comment about another character's facial movements.

Here's a video of the scene, although there are better examples of the abnormal movements in the scene directly before this one.

Whether John Blakely's (Clarence Wilson) facial twitching is acted or hemifacial spasm is not clear. It certainly looks like hemifacial spasm with unilateral clonic jerks involving the eye and mouth. The eyebrow here appears uninvolved although usually it elevates. Most cases are caused by vascular compression of CN VII and a much smaller number of secondary cases follow recovery after Bell's Palsy. Even fewer cases are caused by brainstem lesions. The treatment of choice is botulinum toxin, not available in 1938. As for attributing the symptoms to stress, other than possible worsening in the setting of stress, there's no evidence that rest will cure the symptoms.

Since hemifacial spasm may in a minority of cases represent something sinister, I agree with Mr. Barrymore: "Look out for that twitch, Mr. Blakeley."