Why would she? I mean, sometimes you're just having a good boob day, you know? Kendall does. Last month she wrote a blog post sharing the story behind one of her most famous Insta photos, taken in a sheer shirt with pizza emojis covering her nipples. "I don't know if you can relate, but I just felt like I was having a really good boob day, lol. Do you know what I mean?" she wrote. "Your boobs go through phases and on this particular day, I felt like they just looked nice!" Girl, that is so valid. Good hair days are a thing, and so are good boob days.