Wherever you are, whoever you are, the odds are that you wake up cheerful and get steadily more grumpy through the day - until the evening comes and you can kick back a bit.
Cornell University researchers used Twitter to monitor the attitudes of 2.4 million people in 84 countries, and found that work, sleep and the amount of daylight all go to shape emotions such as enthusiasm, delight, alertness, distress, fear and anger.
The findings may not me much of a surprise, but they mark the first time a study on this scale has ever been carried out.
Using Twitter in conjunction with language monitoring software, the team discovered two daily peaks in which tweets represented a positive attitude – relatively early in the morning and again near midnight. During work hours, in comparison, people were pretty gloomy.
Positive tweets were also more frequent on Saturdays and Sundays, with the morning peaks occurring about two hours later in the day. This probably just reflects the fact that people wake up later on weekends, say the researchers.
But the fact that low moods showed up mid-afternoon on weeknds as well shows our misery isn't just because we all hate our jobs.
The same patterns were found in cultures and countries throughout the world, once the local work schedule was allowed for. For example, positive tweets and late-morning mood peaks were more prominent on Fridays and Saturdays in the United Arab Emirates, where the traditional workweek is Sunday through Thursday.
Interestingly, while seasonal variation did have an effect, it didn't seem to be the absolute amount of daylight that mattered. While this had no effect on mood, though, relative daylight did, with people feeling sadder as the nights draw in and more cheerful once the days start getting longer.