Why We Are Bitter
You truly cannot grasp the complexity of emotions that accompanies teaching until you've done it. Believe me, three years ago, I would have been on the "Boo! Hiss!" wagon of do-gooders who thought professors were cold and heartless and students were people, too and bang the drum of empathy and understanding, ad nauseum.
But this explains it, better than I ever could. And this happened to me my first semester teaching (and it has happened at least once every semester since), the only difference being I lived 44 miles away from campus (not 30) and my student called me to tell me she had "something going on" and a colleague of mine saw her walking into Subway at our appointment meeting time. I guess the something going on was lunch. Although I might have been more pissed if it were Homecoming banners.