And then you realized that it was just plain uncomfortable period. Well at least that was my conclusion. 
Surely the fashion for wearing watches on your left wrist is from the times when all watches were clockwork and needed to be wound.
If you have your clockwork watch on your left arm, you can wind it with your right hand, as the windy thing is nearest to your hand.
Whereas, if you wore a clockwork watch on your right wrist, the windy thing is on the side of the watch furthest away from your wrist and so winding it would be a very awkward.
I realise that these days most people wear battery watches, but that’s where I think it comes from.
As a lefty the things I carry are done by my left hand. If my watch were to be on my left then I would spill my coffee every time I check the time.
I’m a lefty and wear my watch on the right hand.
Interesting, my handedness. Although I write with my left, I do many other things with my right, for example, eating and all sports activities. Which is fun when I am in a Chinese restaurant. Because chopsticks are similar in feel to writing implements, I use those with my left. However, when I get frustrated and pick up a fork, I use my right. And at times, I do both at the same time. Very efficient.
Oh, and in addition to writing with my left, I also use my left for all excretion-related functions. And I mean [ahem] all functions. :eek:
I think you’ve got the cart before the horse. Watches not designed to be worn on the wrist typically have the winding stem at the top. When wristwatches were designed, the winding stem had to be moved to allow for band attachment. Logically, right-handers would wear them on their left wrists, which is more practical because their right hands were more often doing something (a watch on the most-used hand would be less available for viewing and more susceptible to damage). Naturally the stem would be placed on the right to accomodate this.
This is fascinating. Thank you everyone for your replies, and keep 'em coming, please.
But that would be so much more fun when someone asks you for the time. :eek:
I’m a leftie and wear my watch on my right wrist. It just feels comfortable there. My rightie b/f also wears his watch on his right wrist.
Lefthanded, left wrist.
When I was young, I wore a wind-up watch, and I wore it on my right wrist. It was damned near impossible to wind up or adjust when I was wearing it, because the dial is on the right side (try to mimic adjusting a dial on the right side that’s on your right wrist - awkward to the extreme). I switched to my left wrist, where watches are designed to be worn.
You can get right-wrist engineered watches.
Lefthanded, right wrist.
I wear my watch on my right hand for three reasons: One, I’m very doninantly lefthanded, so my left hand is usually occupied. If I want to check the time, it’s just easier to shoot out my right wrist than to stop what I’m doing.
Second, when I was a kid, watches had straps and buckles. Because my right hand was so poorly coordinated, it was easier to use my left hand for buckling the strap.
Finally, as others have noted, it keeps me from constantly banging my watch strap every time I move my left hand.
Lefty. Watch on the right.
Primarily because the left hand is the active one. Swings the hammer. Reaches behind things. Sticks screwdrivers into electrical boxes. Levers the wrench, etc.
But really it all began when I was kid. I played a lot of ball after school. My folks gave us a wristwatch to keep up with the time and it interferred with my slingshot delivery. Moved it to the right wrist for convenience sake and it’s been there ever since.
Thanks for asking.
I’m a rightie who wears it on his right wrist. I can’t keep it on my left wrist for more than a minute without it driving me crazy. I started wearing it on my right wrist because I was a kid when I got my first watch, and my thought process was, if I am right handed, then I wear it on my right hand. Makes sense, right? It never gets in the way with writing or any other activity, so I don’t see why the left wrist is the norm for right handed people.
Another righty who wears her watch on her right wrist. (For about 30 years now)I have had people ask me if I am a leftie. Sometimes I say yes just to avoid the looks I had gotten when I said no. People expect an explaination about why you would ever wear your watch on the hand you write with.
Lefty, watch on right wrist. It’s all about the writing. And I do get annoyed that the little knob (for setting watch) is on the right side of the watch, because that makes it more difficult for me to set it (cause my left hand has to cross over the watch face and it’s all awkward and everything).
And I have to take exception to the OP’s term “bi-dextrous”. Dexter means Right, so you’re being left-ist when your way of expressing that both hands work equally well is to use a term that was obviously thrown upon us by the right-dominated hierarchy. “Ambidextrous” is an insult to those of us for whom our left hand is our dominant, more agile one. Help, we’re being repressed.
(I have related problems with the meanings of the words “gauche” and “sinister”, the term “left-handed compliment”, and so on.)
Sorry Pablito, but I have to work within the confines of the language I was given when I came to this planet.
Another rightie wearing his watch on his right hand. I just do it cause I was mimicking my dad who gave me my first watch. Why ever he did it, I don’t know.
I did hear the “but you can’t write and look at your watch at the same time!” argument a few times in school!!
Oh, and a quick summary of the replies in this thread sofar (yes, I am EXTREMELY bored at work today) gives the following results:
Out of the lefties, 77% wear their watch on the right hand.
Is it not quite simple? Most people wear their watch on the hand they dont use as much, because there’s less chance of damaging it. That’s what I was told when I was a kid. Obviously there’s always some rebels who chose to be different, and they probably damage their watches more often… 
I’m right handed and wear my watch on my right arm. This is a habit that started in my school days when I used to carry my schoolbag on my left shoulder with my hand under the strap, making it impossible to read my watch without shifting my schoolbag.
I’m a lefty, but I’ve always worn my watch on my left wrist. I can’t really tell ya why though…
I’m a lefty but I write with my right hand because in first grade the teacher said to pick up the pencil with your right hand and write -so I did. When I use to wear watches, I wore them on my right wrist because it felt uncomfortable to wear them on my left wrist. It’s easier for me to make left turns when I’m driving then to have to turn right. I knit left - going towards the left direction. When I was a kid and took a tennis lesson - I wanted to hold the racket in my left hand but was discouraged to do so. AHA moment - no wonder I was such a lousy tennis player!
In addition to damage potential, if the watch has a strap with a buckle, then it is easier to fasten the buckle with the dominant hand, thus the watch needs to be on the non-dominate side for easiest buckling of the strap.