How about the counterintuitive fact that when you go faster in orbit, you actually wind up with a slower speed once you reach your new orbit.
Going from 100,000m to 300,000m and to get there you need to speed up, but once there your speed is maybe 1/3 of its previous. But even though you have lower velocity, you are actually having a higher orbital energy. Its just that most of your velocity got converted to potential energy.
Don’t believe me? Cancel out the tangential velocity of your orbit. See how fast you are going by the time you hit atmosphere :)
It intuitively feels wrong to speed up but wind up slower in the end. But when you realize the ISS orbital period is 90 minutes while the moon is 28 days, then it starts to make sense. That moon may be slower, but it has a lot more orbital energy locked up as potential energy.