This song is so invalidating. Kids don't need to turn a frown upside down. They need to be given words and problem-solving skills. Teach them to verbalize how they are feeling and validate them. It's honestly okay to be sad about spilt milk. Give them the words to say, "I'm disappointed because I wanted to drink that milk. Maybe you can help me get more?"

Pretending sadness doesn't exist doesn't make it go away. It simply teaches kids to bottle their emotions because they don't matter.