One thing I hardly ever see in spec screenplays - TV or features - is a reversal. Some writers believe reversals only have a place in horrors or thrillers; other writers sometimes confess they're not really sure what a reversal is, suggesting instead they must be an "American thing"... Yet neither of these assertions are true.
Here is a good definition of a reversal:
A place in the plot where a character achieves the opposite of his aim, resulting in a change from good fortune to bad fortune.
From Screenwriting Info's Glossary of Screenwriting Terms
The operative words there? "The opposite of his (or HER, ahem) aim". In other words, take the reader (or audience) into a scene thinking something is going to happen (usually via the protagonist, but not always) and then CHANGE THAT EXPECTATION - or reverse it!
Obviously thrillers and horrors have the most *obvious* reversals, because this idea of going from "good fortune to bad fortune" is often literally LIFE OR DEATH. In Die Hard, John McClane comes across Klaus in the top floors of the building - and Klaus doesn't have his gun (reversal #1). We THINK John McClane will bust Klaus right away, but instead he accepts Klaus' claim he is a renegade hostage too and EVEN GIVES HIM A GUN (reversal # 2). That's it now... Klaus is going to shoot McClane. Shit! But oh no -- McClane had already busted him previously because he HASN'T LOADED THE GUN... A TRIPLE whammy of reversals. Nice!
But all other genres can have reversals too, even dramas -- in fact, they SHOULD, it keeps readers/audiences on their toes. The more you can SURPRISE a reader or viewer, the more they will think of your story FAVOURABLY. Consider all your favourite movies and TV -- have they used reversals? And if so, how?
ON THE WEB:
All About Reversals - Associated Content - some great stuff here
17 Reversal Ideas (PDF) by Sherri Sheridan - handy & short printable guide, put it on your wall!
Reversals R Us by Your Screenplay Sucks - an interesting real life anecdote that ends by asking, "If this was in a movie, would you believe it?"