Me: Trin, you might want to go in the bathroom and wipe your face. You have a big glob near your mouth.
Me: Did you brush your teeth this morning?
Me: Well, that's what it must be from, then.
*five minutes later, after she puts her shoes on*
Me: Trin, please go in the bathroom, look in the mirror, and wipe that glob off.
Trinity: Why do I need to look in the mirror?
Me: So you can see where you need to wipe.
Trinity: How do you know it's there?
Me: Because I'm looking at you!
Trinity: But I brushed my teeth last night. And I wiped my face last night.
Me: I know you did. And you also brushed them this morning.
Trinity: How do you know that?
Me: Because you told me! I asked you if you brushed your teeth this morning, and you said "yes." And now you have a new glob.
Trinity: *blank stare*