The 'What if' (and other W's) Factor

W - What if, when, who why, where...

I was reading some old writing articles the other day and came across the 'write about what you know' advice. I think it should be amended to 'write about what you'd like to know' and what others might like to know...
The former overused adage, I believe, can easily block a writer and tie him/her to the mundane things in life - a perfect reason for a reader to become bored and put a story to one side.   People read to learn something or be entertained and unless you can add an element of difference, they will soon be unengaged.
The latter phrase 'write about what you'd like to know' may encourage a writer to think more about what makes interesting reading and may help to stop the same old tired plot lines being re-hashed.
After all, stories about futuristic scifi, vampires and ghosts would have never been written if we steadfastly stuck to 'what we know'. And writers like Stephen King and Dean Koontz would be drawing unemployment checks!
Readers want to be taken out of their normal everyday worlds whatever the genre - whether it be soap stories, romance, adventure, mystery, or thriller. These genres still need some 'out there' plotlines or at best some exageration (or almost unbelievable aspect) of everyday life.  Even the soaps, meant to be a representation of ordinary folk and ordinary life, stretch our sense of credulity to the limit. 
Of course, introducing fanciful aspects is where the imagination comes into play. And this leads directly away from the 'write what you know' adage and invites you to ask the 'what if' question. For me this is the most exciting part of writing - allowing imagination to soar to the heavens.
I believe the 'what if' question should become the most asked question by fiction writers, whatever genre they write in.We need to make our stories as different as possible if they are to be noticed.
Asking the other 'W' questions also helps to add spice to a plot. Whenever I am planning a story they are the questions I constantly ask myself, but the 'what if' question is the most fascinating as you can let your imagionation run away with you and maybe turn a plot totally on it's head!
Having said that, readers do still need some elements of familiarity and stories still need to be believable - i.e. could it really happen like that? So 'write what you know' should still be in the mix.   I mean, what's wrong with setting 'kitchen sink dramas' in a futuristic world peopled by aliens?? What if that could really happen....

What do you think? Do you ask that question to get something different from your stories?