Mood-changing nail polish is nothing new, but I think we'd all like to know: Does it actually work? I painted my nails with some (so-called) mood-changing purple polish, and then my production team at Refinery29 planned five mood-changing surprises to test it out. First, a giant pizza pie was placed in front of me. I was excited, but my nail color didn't change. Next, my best friend from college miraculously showed up behind me. I screamed (and cried), but still, no change. Check out the video to see the other surprises — hint hint, there is a puppy involved! Spoiler alert: The mood-changing polish didn't work at all. A little birdie from the Refinery29 beauty team told me that mood-changing polish is actually thermochromic (a temperature-sensitive compound that changes with exposure to heat). Unfortunately, my polish didn't change color during the experiment, but when I left for the night and went down into the hot and sticky NYC subway, I looked down and (what do you know?) pink nails!