A: You should put away those chips.
B: Why? I'm hungry.
A: You'll leave crumbs everywhere.
B: Someone will pick them up.
A: Probably roaches and vermin.
B: There are no roaches on the bus!
A: That's only because people work to keep things clean.
B: You're exaggerating.
A: There are signs saying no food on the bus.
B: No one takes those signs seriously.
A: Imagine if everyone left crumbs and trash on the bus.
B: I guess I should not make a mess at least.