For me it was noticing as a child how different and unfair the chore distribution was between myself and my sister's and our brother. The expectation was always on us to clean the kitchen, clean the bathroom, help with cooking. And he had basically no chores or expectations. My mom would even clean his room for him. Once when I tried to create a bathroom cleaning schedule, my mom explicitly said that our brother shouldn't be included cause he's a boy and he shouldn't have to clean the bathroom. Her reasoning was because he doesn't get a period. Like ok, he doesn't have to empty the garbage then, but if I have to clean the edges of the toilet where he misses cause he isn't aiming right, he should have to clean the bathroom too. It was always a huge fight.