Random question, just because I'm curious...
Who here has genuinely been seasick before? I've been on a boat a handful of times now with no trouble, but the last boat I tried to go on was this dinky thing with a bad motor on it and we went out in choppy waters, and somehow it just didn't sit right with me. I got seasick as heck. It's one of the worst feelings in the entire world, seriously.
Weirdly though, I tend to do better on the smaller, faster, bumpier boats than I do on the big slow ones. Every time I go diving with my family, we ride fairly small (not like motorboat small, but not anything you'd call 'big' either) boats out to the dive sites, and I'm aways fine, even though it can get a bit bouncy at times. Although, that could just be because doing that you're never on the boat for more than a hour at a time, max.
However, the few times I've ridden bigger boats (an overnight ferry to Nova Scotia, a mid-sized boat in the Galapagos) I've invariably gotten seasick. I think it's because of the long, slow, rolling motion of such boats, which is too subtle to really see, but you can feel it in your inner ear; so your eyes are saying you're standing still, while your ears are saying you're moving... with predictable results.
Nowadays, I just take a bonine whenever I'm going to be on a large boat (or a smaller one for any real length of time).