A lot, judging by numerous scientific studies and less scientific surveys.
Halloween could help to collect a wide range of extreme facial expressions, including highly negative situations when children discover their parents ate up all their Halloween candy. This is what was done in the recent paper published in Emotion, the journal of American Psychological Association, and in an ongoing Jimmy Kimmel's challenge pictured above.
Smile! In the era of the Internet of things we are been watched. And our facial expressions show how we feel. Artificial Intelligence is quickly becoming more proficient at recognizing micro-expressions of human faces, mastering emotional intelligence and resurfacing our fears of humanity's extinction. But are we there yet?
The Halloween emotions paper shows that even if you are not a poker player or a strategically-controlling-emotions athlete, just a simple kid, isolated facial expressions may not tell the whole story.
Retail trends provide additional insights - telling that the 11-year reign of princesses is over, as superheroes are now more popular than ever. It's a digital geek-centric age after all.
Still, all those techno hipster and simply magical characters always bring Halloween fun.
And most importantly it teaches once again that you'll get further with treats than with tricks. Diversity is not optional!