Never got seasick, that doesn't mean that I don't, it just hasn't happened yet.
Came close twice, once while in a small compartment trying to do untangle some straps in 10 footers while my co-worker was throwing up in the trashcan, once doing chartwork in a small boat with seas off the beam.
IME focusing on small precise things throws off your equilibrium 10x worse, I've delt with big seas but when I'm not focused on something small (literally) it's more an annoyance.
Then there's guys who lose their shit as soon as the waves hit.
14 years and counting in a Sea going military service.