More sad

Ruby is obsessed lately with being sad. She responds immediately to pictures of sad looking people or animals, and starts to fake cry, saying things like "moon man sad" or "bunny sad". If I try to turn the page, she turns it back frantically, saying, "more ruby sad!" It kind of goes against my instincts, but I try to just let her be sad now (I used to try so hard to tell her, no, the bunny is happy now, Ruby can be happy now, etc). Sadness is a perfectly valid emotion, after all.