With respect to motion sickness, I've found that between the instant torque and the high level of regen, it is easy for the driver to cause more sudden movements for the passengers. Especially new to Tesla drivers that are not used to gently backing off the go pedal. Since the driver is usually the one in control and can anticipate, the driver doesn't feel the effects. So several suggestions - don't abruptly take your foot off the go pedal... this may mean starting to slow down earlier, or learning to hold the go pedal at or near the "coasting" position. Try to avoid launching the car (might be hard to resist) when passengers are in the car.