Murphy's Law In Library School

Class today = full of weird occurrences (though in hindsight, very typical in a Murphy's Law kinda way).
First, our prof brought us cupcakes. Sure it was St. Patrick's Day, but really, when's the last time a prof supplied cupcakes.
Second, two people had their cell phones go off, twice each. Surprisingly, this never happens in class either.
Third, someone loudly choked on their coffee, causing ever one to stare and the prof to comment. Also a first time occurrence.
Fourth, even though we're usually very good at answering question in class, this morning everyone was suspiciously silent (think crickets chirping).
Why? Why did all these weird situations occur today of all days, especially since they've never happened before?
Simple. The prof was being observed and assessed by another prof who was sitting at the back of the class (thus thwarting our note passing, and it's a good thing curling wasn't on). Ah, the memories of teaching.
It's nice to know they get observed. Too bad today's prof was a gooder - how come no one observes the crappy professors???