When you watch Cookie Monster on Sesame Street merrily devouring cookie after cookie, it looks utterly irresistible. That mess of crumbs, that grab of sweet dough, it all feels like pure childhood joy ...

Add Yahoo as a preferred source to see more of our stories on Google. jwray / iStock / Getty Images Plus via Getty Images When you can't decide between a cookie with peanut butter, oatmeal, chocolate ...