Forget the fact that Emma is eating cheetos (it was a special treat she got to choose at the market yesterday), and that I let her have them before her sandwich.
I hear some version of this at least 5 times a day:
Me: Emma, you promised you would eat your sandwich if I gave you some cheetos.
Emma: But I'm done. Can I have some candy?
Me: You need to eat your sandwich.
Emma: No... I just want some candy.
Me: You can have some after you eat your sandwich.
Emma: If you don't let me have some I'm going to make this face forever.