Maybe I’m alone in this, but when I notice a change in someone’s behaviour, I start to wonder why. If a young woman starts to drink more milk, maybe she’s pregnant (I’ve been right about that more than once). If someone starts to wear perfume or change their hair, maybe they are in love.
So for today’s prompt, have your main character notice a change in behaviour in someone they know. And have them completely misinterpret the reason for the change. In order to have conflict, does your protagonist say something to another person (possibly the one the noticed the change in)? Is the conflict internal (they want to ask, but are afraid/shy/think it isn’t the right thing to do)? Go, write a scene.