system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we sometimes produce tears when we're laying down on our sides? Or is that just me?
gpt
Your eyes' "drainage canals" (where the tears drain) are located on the sides of your eyes next to your nose. When you are laying on your right side, for example, your right eye has to work against gravity to continue the normal process of draining old/excess tears. This just makes it a little easier for tears to "leak out" in the direction of gravity (that, and the shape of your eye at its outermost points).