When you have one child and you capture a nice picture of them it's a good moment. You're happy and pleased as punch.
When you have two children and you capture a nice picture of both of them--a picture where they both look human, both are looking into the camera, both are sitting properly, both are almost smiling, and neither one is poking random objects into the other's orifices--you better believe it's your favorite moment. And trust me, it's just a moment. Ten seconds later all hell breaks loose and life returns to normal.