When my sister and I start laughing, we can't stop. It doesn't matter who is around or where we are, it just happens, and it's uncontrollable. We were on our way into our grandmother's funeral, and we had to stop in the parking lot because we just looked at each other and started laughing. We couldn't get our shit together, and our cousin came out and saw us. He gave us a stern look which made us laugh even harder. It's terrible, and I'm ashamed, but you all know that kind of laughter that can't be controlled. I cannot be around my sister when it's a solemn occasion. She starts it.