What game mechanics did you not notice even hundreds or thousands of hours into the game?

Question inspired by another thread. I'll give some examples for myself:

\* Passing time in a car gives you a +3℃ warmth bonus if you select the sleeping bag option, even without a sleeping bag in your inventory. I only noticed that after roughly 3k hours of gameplay.

\* Running gives you a tiny warmth boost (less than 1℃) that can tie you over from freezing to not freezing if your perceived temperature is at 0℃. I noticed this after 3-4k hours of gameplay.

\* The back office and garage part of Quonset is less warm than the store and bathroom area. I noticed this somewhere between 4-5k hours of gameplay.

Honorable mentions: I did not notice the charred body in the attic of the PV barn in many runs, even though I always went up there to loot the backpack.

I wasn't aware until recently, that some visually open ovens, fridges and drawers can be looted (somehow it's only sometimes though).