As we get older, we start to become embarrassed by things that used to be normal.
In movies, there's a common trope where a child is newly embarrassed by having to kiss their mom or dad when being dropped off at school. It's so common because it's so relatable. We all remember the point in our lives when familial affection started to become more private than public.
For one pair of siblings, that moment has been captured forever on video.