I only noticed this now. Blizzard implemented NPC vendors that sell a potion that ‘magically’ removes some situational effects that could induce motion sickness.
I like how it is done in-universe, in the Helmaw with a ghost NPC on a ship. (It’s also generally a peculiar phenomenon how that rocking ship visual can induce motion sickness for some while for others that requires actually being on a rocking ship.)
Extra-humor: In order to prevent the NAUSEA of motion sickness, you drink a potion that smells like toad’s breath and talbuk sweat.
The balance part of the brain takes in information from multiple sensors. The eyes being a major one, in the ear there is another major balance organ (kinda like a gyroscope, 3 loops filled with fluid). Laymans explanation as to the to phenomenons you mention.