Perhaps you have had the unfortunate experience of being on a boat and getting sea sick. I always joke with my customers when I tell them I have never met anybody weaker on the water than me! I used to get very seasick. I would often be sick before the boat even left the harbor! I know that some of it was mental but fortunately for me, being on boats in rough seas finally got me to the point where it does not bother me anymore. Not only does it not bother me but I can not understand why it did in the first place! I have had a few times where I actually had the opposite happen to me. When I worked on the tug boats I would often be on the boat for 2 weeks or more at a time in very rough seas. I got so used to walking on the boat when it was rough that when the boat would pull into port and I could get out I actually got land sick! When I took a step I was used to the deck of the boat meeting my foot before I put it down but for the first 10 minutes or so I looked like I was drunk! That part would usually pass fairly quickly but it took me a while to get used to being on solid ground again and I would actually get a “queasy” feeling because there was no movement. I still have that sometimes if the seas are rough when I work on the submarines because I am usually on the water for about 10 hours. I don’t know what would happen to me if I was on the water for a month or so at a time!