Zooming in a little further, the five most common types of coincidences were:

Sharing a birthday with someone (11 percent) Connections involving books, TV, radio, or the news (10 percent) Vacation-related coincidences (6.1 percent) Meeting people while in transit—while walking around, in airports, or on public transportation (6 percent) Coincidences related to marriage or in-laws (5.3 percent)

Some of these categories are admittedly a little fuzzy—any number of coincidences could befall you on vacation!—so perhaps it would be better to say these are the most common themes that appear in coincidence stories.

“I bet most of the vacation ones concern meeting people with whom they found a connection,” Spiegelhalter told me in an email—that’s a type of coincidence he’s seen a lot before.

Here’s a map Quid made of the full data set:

The Top Coincidence Themes and Their Connections

Quid

Each dot represents one story, and the lines connect stories that have very strong linguistic similarities. So the light blue birthday cluster is tightly snarled, because there are only so many variations on finding out you share the same birthday as someone else. But the red cluster of shared death dates has some connections to the birthday cluster, indicating that some coincidence stories involve both birth dates and death dates.

These results also offer a possibility to study some coincidences more quantitatively—“the 28 percent of stories concerned with dates and numbers suggest this is a very popular source of surprising matches, and this proportion could be subject to statistical analysis,” Spiegelhalter writes.

The researchers also looked at the tone of the stories, and found that more people described their coincidences using negative language (32 percent) or neutral language (41 percent) than positive language (25 percent). It seems coincidences are not always fun meet-cutes or pleasant surprises.

Along those lines, the word “die” appeared more times in the dataset (373 times) than the word “love” (220 times).

“I was anticipating seeing more Harry-Met-Sally type tales about love and destiny,” McCuan wrote. “But they were harder to find.”

It’s unclear why that is, but some research shows that people who are seeking meaning are more likely to experience coincidences, as well as people experiencing extreme emotions. So when people are in distress or flailing about looking for a sign, perhaps the sign they get is not always the one they’re looking for.

Or maybe it’s because what makes coincidences special is that they present a piece of evidence that the world doesn’t work how you thought it did. Did you run into your friend at the grocery store because cosmic forces were pushing you two together? Did you hear the same song everywhere you went one day because it contained a message for you? Probably not, but it can feel that way, at least at first, and that’s what makes a coincidence startling. It’s unsettling to feel a ripple in the fabric of your reality.