An anonymous shares a report: People who are miserable on Monday have lots of company. It's the worst day of the week for millions, according to researchers at the University of Vermont Complex Systems Center who analyze Twitter messages for happiness sentiment. Mood tends to improve during the rest of the week, peaking on Saturday, before beginning to crash again, according to data based tweets since 2008. In this analysis, the university's "hedonometer" takes a random sample of about 50 million Twitter posts each day, which is roughly 10% of all the site's message traffic. The researchers have assigned average scores to more than 10,000 commonly used words (from 1 to 9, on a scale of increasing happiness), which are used to measure a particular day's happiness. The data can also offer some insight into how populations have responded to major events. The day after the mass shooting in Las Vegas on Oct. 2 was Twitter's saddest day on record, according to the University of Vermont research. Another low was recorded on May 2, 2011, when Osama Bin Laden, the terrorist mastermind behind thousands of murders, was killed. Rather than clear positivity, language used on Twitter "reflected that a very negatively viewed character met a very negative end," according to the researcher's website.