Lavin very funny only at times, as if they restricted her.

I think it was just her character IY and how the writers and Lavin chose to portray her. I used to watch this show, but it has been a long time since seen and I can barely recall her. Wasn't she a sort of laid back and easy going character with a dry and also sarcastic sense of humor? I also think she had a straight laced side to her personality and was the moral\dramatic voice of the show. Flo was feisty, cut to the core with her honesty and wit, and this made her appeal more endearing to many.

Exorcist: Christ's power compels you. Cast out, unclean spirit.
Destinata:💩

Yes, I think these shows have episodes like this to prove to naysayers that although the star is playing 'straight man' or 'straight woman' they really are more dimensional. It's kind of refreshing and because it only happens occasionally, it does make these episodes noteworthy and stand out a little more.

I'd say Linda Lavin is like Andy Griffith in this regard. Very funny in their own right, musically talented, playing a hard-working and decent person, clearly the star of the show, but usually reflecting the jokes, instead of cracking the jokes.