system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does liquid sometimes pour straight down the sides of a cup when held diagonally, instead of straight down where we’re actually aiming?
gpt
Water likes to stick to things (that's why it runs down your arm in the shower). Pour spouts are shaped so that the water can't grab on. If it doesn't have a spout, you have to turn the cup almost upside down to prevent it from holding on to the glass (like it does in the shower).