Line: That's very convenient.
Context: An a-ha! moment for Michael as he hears an echo of his own words from the mouth of his nemesis, jerk director Ron. In the original iteration, Michael defends his lying to Sandy and spending a weekend with Julie by saying, “I never told Sandy I wouldn't see other women. Come on. If I told her, it would hurt her and I don't want to do that. Especially since Julie and l are just girlfriends.” See how that works? He commits lie of omission that is actually a compassionate act. His friend Jeff worries he will go to hell for it, but Michael doesn’t believe in hell—only unemployment (see Lesson Twelve).
But then he sees Julie going through hell in her relationship with two-timing Ron and is forced to reassess. Full of righteous fury on behalf of his girlfriend, Michael tells him, “I don’t like the way you patronize her, I don’t like the way you deceive her, I don’t like the way you lie to her.” Ron replies with a familiar excuse.
Ron: Look, I never promised Julie I'd be exclusive and not see other women. But I know she doesn't want me to see them so I lie to her to keep from hurting her.
It’s a reproach, but it is also the beginning of insight. Just the beginning, however. When he sees Sandy later that evening and gives her a box of candy she asks him if that means he thinks nothing’s wrong. He says, “Nothing is, is it?” without remembering his lies, deceptions, and patronizing behavior.
Usage: While this would seem to be a line exclusive to masculine use, it’s not necessarily so. Sandy and Julie were clearly reluctant to scrutinize Michael and Ron’s actions. They avoided confrontations that might result from little hurts and allowed themselves to be sandbagged by the collective big one. Sometimes it’s as convenient to believe a lie as it is to tell one.