system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why it's very hard to open the freezer right after you close it?

With 'right after' I mean something like 'a minute or 2'. It happens when I take an ice cream out of it (freezer) and then put it back in the freezer.
gpt
The freezer is full of cold air, if you open it, some warm hair gets in.

Close the freezer again, and the warm air inside it cools down, somewhat quickly. That means, it shrinks and uses less room.

You create a low pressure environment inside your freezer, so it's harder to open the door than usual. Over time, more air will leak into the freezer until the pressure evens out with the outside.