system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is it that when we put cold feet in hot water it feels like it's burning more, but when we put hot feet in cold water it's relieving?
gpt
The direction of heat transfer.

When you're putting your cold feet in hot water, the hot water is transferring its heat to your feet and trying to reach equilibrium. There's a huge difference in temperature between your feet and the water so a lot of heat is transferred, so it feels extra hot.

The opposite is true when you put hot feet in cold water. The heat in your feet is being dissipated through the cold water.