If only...

Science fiction writers construct stories around the phrase "what if?", but the phrase "if only" can be just as powerful a trigger for our writing.  A character regretting something they have done or haven't done can powerfully drive their motivations, and your narrative.

How often do we hear "if only I hadn't married him/her"?  What would we, and our characters, be like if we hadn't had this trial by fire?  Different, certainly, possibly more trusting, perhaps still believing in romance,

We will see lots of "if only" stories this year with the centenary of World War 1.  We'll hear from women who lost the only love of their lives on the front.  We'll hear stories from people who regret not defying their parents and getting married before the man went to France.  "If only we'd run away from our parents, and had some stolen time together."

If only is a product of hindsight, we regret things through the lens of history.   Twenty years later we might have a character looking back and wishing that a once-close friendship hadn't soured.  If its loss, and your character's bitterness over it, have driven his actions ever since, will he try and make amends?  Is the friend still alive to approach and apologize?  Or did he or she die recently, so he'll take his regret to the grave with him?

In Panthera : Death Spiral, Ren Hunter has been estranged from her brother Nic for years.  When they finally reconcile she still regrets the missing years when they had no contact.

If only I hadn't said that.  If only I'd been born into a rich family.  If only are regrets powerful enough to shape our characters' lives, and to make us as readers care about how they feel.