That must have been 29 years ago when I took Thermo, but I'm pretty sure I didn't understand anything "right away" without some deep thoughts.
I do recall one time our Thermo professor was being a smarta$$ and asked us with a serious straight face, "If a car uses half a tank of gas going uphill, does the tank of gas become full again once the car goes back downhill?"
We're all like, "Are you serious?"
These days, the 2nd law of Thermodynamics is on continuous display in my oldest daughter's room.