Roger Moore was the first James Bond I saw, and though he didn't last as my favorite Bond, he did sustain the franchise from 1973 to 1985, playing Bond in seven authorized films, more than anyone to date (Sean Connery's seventh film, Never Say Never Again, was not authorized). In that time, Moore broadened Bond's sense of humor and thus his appeal. No one can wrinkle his nose and smirk with disdain better than Sir Roger.
By the same token, Moore is probably most responsible for turning Bond into a caricature, a reputation that followed the character until 2006's Casino Royale. Moore hates shooting firearms, which caused him to ruin countless Bond takes. All the scenes that involve running in his seven Bond movies were performed by doubles as he felt he looked awkward running. He hates being wet while acting, not the best quality for someone playing a Royal Navy commander.
But it seems Moore was in on the joke:
"To me, the Bond situations are so ridiculous, so outrageous. I mean, this man is supposed to be a spy and yet, everybody knows he's a spy. Every bartender in the world offers him martinis that are shaken, not stirred. What kind of serious spy is recognized everywhere he goes? It's outrageous. So you have to treat the humor outrageously as well. My personality is entirely different than previous Bonds. I'm not that cold-blooded killer type. Which is why I play it mostly for laughs."
And all his quirks may make him the most memorable actor to play Bond.