This is a question that all of us ponder on at some point of time. There is one famous answer, which is that the watch-makers want you to smile. They want people to remember that they should smile and look at their watch. I was also quite satisfied with this answer before.
But, the actual answer comes from marketing and branding.
The moment you see a watch, you always see the time and get distracted by the time. So the watch-makers had difficulty to make consumers see the brand, the watch, and appreciate the watch without getting distracted by the time. The watch-makers decided on a time 10:10 which pretty much focuses on the maker’s name. If everybody uses the same time, then the consumer will see the brand, the watch, instead of the time on the watch. It is just to avoid consumers getting distracted by the time. This is the rationale behing 10:10.
This is one of the lessons of how intensely one has to observe consumers. Thank you.