A Smile
A smile is the fake happy face people show you so you don't realize they're dying inside. It's like when your mom says she's fine, but you know she just got fired and her dog ran away.
My boss smiled through the whole meeting, but I could tell he wanted to punch the wall.
My ex smiled at me, but I could tell she was thinking about how I broke her heart.
My teacher smiled at me, but I knew she was just tired of grading my nonsense homework.