On the day I got my PhD, the first thing my mum said to me when I rang to say I'd passed was, 'Oh, I do hope you won't call yourself Dr, it's so pretentious...
...and congratulations!'

Anywho, I never get called Dr except on my office door and in rejection letters from journals. But I think most academics do use it in civilian life. I kinda want to. Does this make me a smug git, especially because my subject specialism is in something entirely useless to humanity literature?