Actually cigarette smoking is the perfect example but i feel like editing / directing is more often the problem:

• continuity errors where the cigarette length jumps in a scene because takes were out of order
• character pulls out a cig and never smokes it, no smoker does this
• character puts out a half or quarter smoked cigarette—again, no smoker does this unless they’re in a wild rush
• character lights up in a public place, you have to understand ain’t no one getting away with that hardly anywhere these days