How about "It Happened One Night" (1934) - Not Cary Grant but another guy with the initials of CG, Clark Gable with a sizzlin' Claudette Colbert showing how to stop traffic.
As for "Arsenic and Old Lace", watching the hero trying to keep it together when his entire world is collapsing into chaos on his wedding night is WOW! This is a comic tour-de-farce!
I love that hitch-hiking scene! :-)