APIs
Although there are more useful and important possibilities within the API, I chose to highlight the Traitify for its interesting function—a personality test. The listed potential uses include matchmaking, marketing/sales, and behavior predictions.

The interesting thing about this supposedly psychology-backed data base is that they assess results by having the user select "Me" or "Not me" upon a series of images. I am just curious about what images pop up, whether they are cheesy stock images that show obvious emotions such as extroversion and introversion, or if they are more subtle and subconscious visual cues. The images shown below present some of the features of the API.
As someone who love to take these personality tests, I am curious about the details such as "What Brightens/Clouds Your Day". The "Famous People" match, however, makes me super suspiscious about the accuracy and trustworthiness of all of these results, since there is no way that all of these famous people, some who are long dead, would have taken this test.
That being said, I find it an interesting idea to mix psychology with technology to detect a user's personality trait or tendency. I would imagine not a straightforward test, but a simple simulation game that could subconsciously show one's traits. It would maybe be even more accurate if time was a factor, since people act differently in real life as opposed to a simulation, where you can calculate your results and take time to deeply think.