I've lived long enough to have encountered lots of people that lie. From the point of view of the person who is lied to, lying destroys trust. When you catch someone in a lie, you know you can't trust them to be honest in anything they say. You also know they don't trust you to be able to handle the truth.
Several of my characters lie, but not to be maliciously manipulative. Mostly they lie when they don't know how they feel, when they don't want conflict, or when they don't want to be alone in their opinion or called out for what they've done. They lie out of weakness.
Ironically, the characters that don't lie tend to be brutally honest, unable to filter their words, and tend to come off as being jerks.
Juxtaposing liars against characters who were brutally honest wasn't what I set out to do in my current novel, but it has been fun.
Do your characters lie?
This post is part of the 2012 A to Z Challenge.