Charade (1963)

  This movie almost fails as a thriller because it's just so cute.  How are you supposed to be paying attention to finding a killer when Audrey Hepburn and Cary Grant are trying to out-charm one another?

Regina Lampert (Audrey Hepburn) is a widow.  Worse yet, she discovers her late husband may have stolen $250,000 and no one can find out what he did with it.  Three very unsavory men (James Coburn, George Kennedy, and Ned Glass) begin to harass her all over Paris, convinced that she knows more than she's telling.  Only Mr. Joshua (Cary Grant) seems remotely trustworthy but a man at the U.S. Embassy (Walter Matthau) warns Regina that Joshua is not who he seems. 

I love this movie.  It's a nice palate-cleanser after watching something weighty, like Breaking Bad.  Sometimes you just need a break, you know?  The only thing that ever remotely bothered me about Charade was the May-December romance line between Hepburn and Grant.  I've never seen the appeal in dating someone two decades older than I am, but I recognize that it's a thing that happens.  Plus, I've never found Cary Grant particularly good-looking, even when he was young.  But that's some personal nitpicking, not a real criticism on the movie.