It may not see you when you’re sleeping, but it definitely knows when you’re awake — and how you may be feeling depending on what month and day of the week it is, evidenced by a new collection of data visualization graphs with hundreds of billions of data points, a.k.a. tweets.

Twitter’s Data Editor, Simon Rogers, posted the photos on the social media site’s blog Thursday, showing in a pixelated sprawl of blue hues just how many times people tweet certain key phrases related to happiness, sadness, lateness, and the extent to which they’re hungover. Some patterns are easily explained, while others are more subtle. Of course, for every social drinker-slash-weekend warrior there is a tardy couch potato who does his best work with a headache.

Keep in mind that Twitter data explains just that: what people tweet. Despite what it may seem, people only tweet in certain circumstances, and not all feelings of happiness or sadness merit 140 characters or less. People may simply be too sad or too happy, in fact, to tweet at all. But nevertheless, from the data certain patterns emerge.

Among them: People are most hungover on Tuesdays in January and Thursdays and Fridays in November. People are late for work most often during the summer, and typically in the beginning half of the week. People are happiest Monday through Wednesday in December, but, strangely, saddest on Saturday. Overall, tweets containing “hungover” numbered the fewest. Unsurprising — you can’t tweet if you spend the entire day asleep.

twitter-happy
Twitter isn't just good for 140-character outbursts and breaking news: it also knows when you're happy, sad, and hungover. Twitter
twitter-sad
Twitter isn't just good for 140-character outbursts and breaking news: it also knows when you're happy, sad, and hungover. Twitter
Late
Twitter isn't just good for 140-character outbursts and breaking news: it also knows when you're happy, sad, and hungover. Twitter
Hungover
Twitter isn't just good for 140-character outbursts and breaking news: it also knows when you're happy, sad, and hungover. Twitter