People. Just people being arseholes.
We took our kids to the field behind our house, built an epic snowman - taller than my 8 year old - carrot nose, the works. In the three minutes it took us to walk home, take our boots off and go into the kitchen, some kids had taken the head for their own snowman and were kicking the rest of it down. Watched by their parents, who had been on the field the whole time we had and had watched us build it.
I mean, it’s a public field so it was probably inevitable and it’s only a snowman at the end of the day. But it’s the principle of the thing - watch someone else make something and then with no thought or hesitation, ruin it. Honestly makes me wonder why I bother trying to be a nice, decent person who worries about others when so many self-entitled, selfish idiots just go round doing whatever the hell they like.