Coaster?

So I've had to be at work "early" this week...which pretty much consists of me waking up an putting on the first thing I find in my closet, brushing my teeth and sprinting out the door. The system seemed to work well...until today when I looked in the mirror ONCE I GOT TO WORK and noticed my shirt. Did someone use my shirt as a coaster because how does a perfect circle get on your shirt otherwise?! I'm totally confused, but thankful I can go home and change!