White lies are termites. Each one is tiny, and the house still falls.

Lies told to keep things smooth are the hardest to be concerned about, because each one was meant well. The damage is structural rather than dramatic: the other person gradually loses the ability to read you, since anything you say now carries a small chance of being the comfortable version. Eventually even your honest answers arrive discounted. Nothing visible broke, and nothing holds much weight either.

Start with the low stakes ones, where the truth costs almost nothing. Say you did not like the film. Being someone whose small answers are accurate is what makes the big ones worth anything.