Why Robert Cummings?
If you're a Robert Cummings fan, don't bother reading this.
I thought he was horrible, unable to convey anything other than dorkiness. He seemed like an amateur among professionals. While I don't think Grace Kelly is a great actress, she certainly had screen presence. Even Anthony Dawson as Swann was better. Ray Milland, of course, stole the show. When Cummings whispers "What's he doing?" it sounds like something from a 60s Disney movie or "Leave it to Beaver."
From his first moment on screen, looking smugly left and right as he arrives in England, he is distractingly annoying. There are several moments in this film when his face should display some type of emotion, but his is blank, like Howdy Doody. In his first scene with Grace Kelly, he is very unconvincing in the manner he holds his glass and cigarette.
Phony smoking is a pet peeve of mine. Like fake Southern accents, I hate watching non-smokers pretend to smoke. Watch Bogart. He smokes naturally. (That may be a bad example, because everything he does looks natural.) The cigarette is an extension of a smoker's hand. In non-smokers' hands, it's a foreign object, a prop, something that seems to be their primary, conscious focus. Why was he smoking anyway? There was no need for this character to smoke.
While I can understand a non-smoker being an unconvincing smoker, there's no excuse for someone not to be able to look natural holding a drinking glass! Everyone holds a drinking glass or cup at some point in their lives. And they drink out of them. In Dial M for Murder, between the glass and cigarette, Cummings looks like he's holding two live animals in his hands that he doesn't know what to do with.
Finally, why Robert Cummings anyway? THIS is who GRACE KELLY'S character would have an affair with? Why this dweeb? She could get anybody. Was it Hitchcock's way of not having "competition" for his leading lady? Robert Cummings seems much more suited for bland sitcom dads or a game show host, not someone Grace Kelly(!) is having a torrid affair with.
I still enjoy this movie, and by no means is Cummings the worst ever, but he does make me cringe at times.