Outlook just popped up an error message telling me it couldn't sync a message out to the server. It didn't tell me what message, why there was a problem, or if I should do anything to solve it or if it would solve itself.

This reminds me of an old, pre-GPS joke. Tourists in Seattle are up in a helicopter getting one of those fancy copter tours. All of a sudden, a massive fog rolls in. Visibility drops to zero. The pilot isn't quite sure where they are.

I've decided to share my slide deck detailing my ... concerns about the F measure. tl;dr: just don't. First, some definitions of precision, recall, and F. F is a harmonic mean of P and R. Harmonic means are appropriate for averaging ratios, which is van Rijsbergen's original motivation for recommending F. F is for sets, not ranked lists.