Must Have Been Studying Relativity

(While I was working in the tutoring/study center of my college, at the sign-out desk:)

Customer: *handing me his card* “Aw, yeah! I studied for hours! Must have broken study records! Yeah!”

(He goes on like this as I sign him out and doesn’t slow down after, all the way out the door. My screen shows the duration of his visit.)

Me: *to my coworker* “He was here for 20 minutes…”