I'm not a fan of The Seven Year Itch, which seems so un-cinematic to me that I just can't get past that disqualifier.
I never really liked Love in the Afternoon either, perhaps for the reasons you mention, though those elements don't bother me at all in The Apartment. So who knows?
And for the record, I do and will always watch Sunset Boulevard just to study its cinematic brilliance. Who knows, maybe one of these days I may come to love it. Admire it, I surely do.
…sometimes it's true in great literature that there is no real antagonist, per se. In that case, in my view, it usually means that the landscape of the narrative itself is the real antagonist - the trap that each character finds himself in.
Which raises a question that often comes to my mind when studying such subtleties within a given film: how much was intentional, how much was purely luck and how much the result of something instinctual, of which the director and/or writer may not even have been aware but, somehow, sensed was the right thing to do? It may be a romantic notion, but I like to think that last quality is among the inscrutable things that set the truly brilliant directors apart.
It's certainly one of Wilder's most atmospheric pieces (which appeals greatly to me), working on multiple levels with both the integration and clashes of, shall we say, Norma's world of the past and Joe's of the present, the latter of which is now - ironically - more distant from our viewpoint than Norma's was from Joe's at the '49-'50 point of its production…which adds another level of appeal: that distance now applies 67 years of what antique dealers call "patina" to what nevertheless remains the optimistic vitality of Joe and Betty's story - in contrast to the stifling and desperate stagnation of Norma's - and what was already a thematically rich examination of insular but connected existences at the time of its release.
The man really loved the movies and loved making them, and it showed. He liked to go out a winner; and so he did.
Double Indemnity is numero uno. It doesn't get better than that, imo. (Love the brilliant James Cain novel, too. Worth a read if you haven't read it already.)