I just had a realization and have not found any info on whether anyone else has noticed.
As fans know, Chris Moltisanti thought Tony and Adriana had an affair. Tony was able to convince Chris that nothing had happened, but it created a rift in their relationship. The rift magnified when Tony ordered the hit on Adriana.
Later, Chris created a movie called "Cleaver." In the movie, the main character, obviously an avatar of Tony Soprano, has sex with his nephew's girlfriend. When the film was screened, everyone (Carmela, Jackie Jr.'s mom) noticed the uncomfortable implication, except Tony himself.
So here's my realization. In the Shakespeare play Hamlet, the Hamlet character thinks his Uncle Claudius murdered Hamlet's father. But Hamlet isn't sure. So Hamlet stages a play (play-within-a-play) in which a man murders his brother, as a sort of test to see how Claudius reacts to the performance. I think Chris's motivation in making "Cleaver" was the same. It was intended to test Tony.
There are other parallels between Chris and Hamlet. Both bedeviled with uncertainty, both having murderous feelings toward their father figures, both feeling they had to avenge the death of their real fathers. Hamlet appears to go mad throughout the play, and Chris loses his cool too, even succumbing to drug addiction.
Anyway, I found this parallel quite interesting. And would be surprised if it were pure coincidence.