Why is tanning so popular?

Tanning is a fad that I don't think I will ever get. I don't understand why it is so popular. First of all on people who are naturally fair it looks unnatural and fake. It can give you cancer, wrinkles, and it also give your skin that gross leathery texture. Also, celebrities who are considered beautiful like Megan Fox, Angelina Jolie, Natalie Portman, and Mila Kunis don't tan. So why is it so popular?