Mondays Really Do Suck

This Facebook app's stats show that happiness climbs steadily during the weekend, then drops as soon as Sunday reminds us that Monday is coming. Once the doldrums have past, happiness begins a steady rise.

Also, I wonder if any of these are tied to the sudden dip in happiness on January 22nd, 2008: http://en.wikipedia.org/wiki/January_2008#2008_January_22

Heath Ledger, perhaps?

I wonder what words they consider to be "positive" and "negative".