Are they really that fun? Wouldn't it be more relaxing to put gloop all over your face when you're by yourself? How do you eat and drink while carrying out all those beauty treatments? What's the point of it all if you're going to stuff your face with ice cream and chocolate? And do all women really love ice cream and chocolate that much anyway? 
Sorry there are a lot of questions, I am just hoping someone can explain the appeal and I'm wondering if they're really that commonplace :-)