Things have a nasty 'habit of not turning out' the way you expect them to. [=things often do not turn out the way you expect them to]
He reached into his pocket for his keys 'by/from force of habit'. [=he did it without thinking because it is what he usually does]
I'm 'not in the habit of' making predictions, but I don't think there's much doubt about who will win this election.
(..) - Hurry up! - Fire! And then there's the Monstrous Nightmare. Only the best Vikings go after those. They have this nasty habit of setting themselves on fire. Reload! I'll take care of this. But the ultimate prize is the dragon no one's ever seen. - We call it the... (..)2010 How to Train Your Dragon