[Quick Summary: Alan Turing during WWII.]
Abruptness* for no reason is a useless gimmick.
The reader will feel manipulated (and, in my case, angry at the page).
However, if the trait reveals subtext, it is pure gold.
Here, notice how it shows Turing's inability to read others:
ex. "INT. BLETCHLEY PARK - COMMANDER DENNISTON'S OFFICE - LATER
A few minutes later, Alan sits alone in a cluttered office. He stares ahead blankly at the empty chair behind the desk. Waits.
COMMANDER DENNISTON (O.S.): -What are you doing here?
Alan turns with a start.
ALAN TURING: The girl told me to wait -
COMMANDER DENNISTON: In my office? She tell you to help yourself to a cup of tea while you were here?
ALAN TURING: No. She didn't.
COMMANDER DENNISTON: She didn't tell you what a joke is then either, I gather.
ALAN TURING: Was she supposed to?
COMMANDER DENNISTON: For Christ's sake - who are you?
ALAN TURING: Alan Turing....
COMMANDER DENNISTON: ...King's College, Cambridge. Says here you were a bit of a prodigy in the maths department.
ALAN TURING: I'm not sure I can evaluate that, Mr...?
COMMANDER DENNISTON: How old are you, Mr. Turing?
ALAN TURING: 27.
COMMANDER DENNISTON: How old were you when you became a fellow at Cambridge?
ALAN TURING: 24.
COMMANDER DENNISTON: And how old were you when you published this paper here, that has a title I can barely understand, which apparently got you this fellowship?
ALAN TURING: 23.
COMMANDER DENNISTON: And you don't think that qualifies you as a certified prodigy?
ANA TURING: Rather depends on how old my peers were when they did comparable work, doesn't it?
COMMANDER DENNISTON: And how old were they?
ALAN TURING: Newton discovered the binomial theorem at 22. Einstein published four papers that changed the world at 26. As far as I can tell I've barely made par.
COMMANDER DENNISTON: You're serious, aren't you?
ALAN TURING: Would you prefer I make a joke?
COMMANDER DENNISTON: Not sure you know what those are."
WHAT I'VE LEARNED: Use socially unacceptable traits to show subtext.
(Don't just use it to manufacture a surface conflict.)
The Imitation Game (2014)
by Graham Moore
Based on "Alan Turing: The Enigma", by Andrew Hodges
* Or any character trait, for that matter.