system
Given the following post, respond as if you're commenting on Reddit:
human
ELi5 Why do belly buttons collect lint??
gpt
Most hairs on your belly are growing in the direction of the belly button. When wearing clothes that are susceptible to generate lint while you are moving around the lint can only travel in the direction of the belly button, eventually collecting there.

Having a smooth, hairless belly should therefore also reduce lint accumulation.