Why some people are barefoot all the time, and why Phil failed biology.
If you know someone who always walks around barefoot, there's a chance they're not crazy – they could be earthing.
Earthing – or grounding – is the belief that going barefoot connects you to the earth's magnetic field, which, ultimately, improves your health.
"Earthers" claim that "exposure to the earth's electrons neutralizes harmful free radicals that trigger inflammation and carries health benefits that range from reduced stress to less pain and a better night's sleep." (Yahoo)