I’ve always believed you could tell a lot about a person based on when they laugh. Or if they laugh at all. Laughter provides a brief but in-depth window into arguably the most enigmatic organ in the body—as well as the idiosyncrasies at work for that individual. I’ve suggested before that we adults take life way too seriously . Compared to the average child, who belts out around 400 laughs a day, we summon a measly 15-18 per day. Somehow I think we’re missing out with all that seriousness—mentally and maybe even physically. (This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Tina Leaman)