Mostly when playing games that involve lying. I won't lie to my wife and I avoid lying to my children, friends, and coworkers. I sometimes lie to patrons of the restaurant where I work, to provide a simple-but-false answer instead of a complex-but-true one, but never about ingredients or allergies. A good example is if they ask me how I like the shrimp I'll say I'm allergic but they're very popular. I think shrimp are disgusting and don't eat them, but it's true that they are very popular.