I’m left-handed and wear my watch on my left hand… and i notice that most people do… I guess I’m wondering why this is…
I no longer wear a watch at all (with my cell phone and/or my ipod on me at most all times, I already have a clock handy and have no use for a watch), but when I did, it was always on my right hand. I’m left handed and I didn’t like having to stop writing or worry about tipping over the cup I was holding in order to check the time. Reverse this logic for right handed people to understand why they wear it on their left hand.
I find that if I tense the wrist of my whatch arm I can strain or even break some watch bands. For this reason I wear my watch on my off hand, so that if I need to unscrew a tight jar lid or make a fist, I don’t risk popping open my watch band. This was especially a problem when I had one of those metalic lever type watch bands.
Also watches often have their winders and buttons on the right hand of the face, so they are probably easier to press/turn if the watch is worn on the left hand.
I am left handed and wear mine on my left hand. I have broken many strap links in the past. It might make more sense to be on the right, but I have got used to it being on the left so that’s where it stays.
For every person who follows logic and wears their watch on the off hand, or on the left, for the reasons above, there will be SOMEONE who is right handed and will wear it on the right simply just “because”.
Hi. 
I’m lefthanded and wear mine on the right, because it gets in the way if I wear it on the left.
I am right handed, and when I wear my watch, it is on my right wrist. I have always done this, but I don’t know why. It just feels more comfortable. If I have a watch or bracelet on my left wrist, it feels wrong somehow.
I’m left-handed and wear mine on the right. As with friedo, the watch gets in the way if it’s on the left wrist.
I’m a lefty, and I wear my watch on my right wrist. I used to wear my watch on the left, but I kept banging the watch into things and scratching the face.
My first shot at an educated answer…
When I was a right-handed child, with a dextrous left hand, I wore my watch on my right wrist, because the motion of checking the time on my right was more comfortable.
My friend’s father called me a goof because I had my watch on the wrong hand. He pointed out that most people wore their watches on their left writst, because most people are right-handed, and thus, it was easier to install (put on) the watch using that hand… Same reason shirts button one way, and not the other.
I hypothesize then, that since it seemed almost customary to wear it on the left, lefties wear it there too, so as to not look “off”.
DodgeRam.
I am right-handed and wear my watch on my right hand. Although it’s not just “because.” For some reason I do certain things left-handed. It’s easier for me to put on my watch with my left hand, so I wear it on my right.
I am only posting this because it seems the question in the OP has been aswered (ie. most people are right handed and it is easier to put a watch on your left hand if you are right handed, and if you are right handed you will not spill your drink if asked what time it is if your warch is on your left hand).
You have obviously never noticed how womens shirts button, or are you suggesting that most women are left handed? 
I am right handed and my Rolex never leaves my left wrist.
Because it is tattooed there.
Fourth generation lefty here. My watch is on my right wrist.
If you’re a lefty and wear your watch on your left wrist, you’re not one of us. You must be a spy for the Dark Side.
Some people wear them in the top pocket of their waistcoat.
Others wear them in the “condom” pocket of their jeans.
As to wrist watches, when I carry one, I wear it on my right wrist.
Since I am not sinister, people would call this the ‘wrong’ wrist.
I’m so right-handed that I don’t use my left for anything. Even when I’m driving with my right hand, I’ll (unconsciously) take it off the steering wheel to tune the radio, while my lazy left just sits there doing nothing. So I wear the watch on the left wrist just to force my left arm to get some work in. BTW, somehow my left arm is stronger than my right. Very weird. Perhaps it pays to be lazy.
I’m a righty, and I wear my watch on the kitchen windowsill.
I’m a lefty and wear mine on the right. It never entered my mind that it might look “off,” nor has anyone ever mentioned it, that I recall.
The problem now is that wearing it on the right is uncomfortable when I use a mouse. Yes, I know I could switch the mouse, but I got used to using it right-handed when I shared a computer with my husband.
I’m Right handed and wear my watch on my right hand.
I don’t know why, I just do.
Every analog watch I’ve owned has had the time/date changing stem on the right side. And back when I was a youngun and rode the stagecoach to the general store, watches had to be wound regularly and the winding stem was also on the right-hand side. Right-handed people could easily reach over and wind the stem even while they were wearing the watch.
So virtually all righties wore their watches on their left arm. And most lefties did as well because the stems were easier to manipulate that way. Since you learn about such things by watching your elders, I’ll bet that left-arm watch-wearing was looked at as the norm even when the cause became less important.
Obsolete customs have staying power (see ties: wearing to work) but gradually fade over time (see ties: wearing to work). So it intuitively feels right that most people still keep watches on their left wrists but that the habit is not as powerful.