In the Chinese culture, giving a clock as a birthday present means that you want the birthday person to die soon. Or something to that effect. I can't really remember the exact meaning. But you get the picture.
It kinda makes sense because a clock signifies time, and as it goes "tik.. tik.. tik" you have less and less time in your life.
I always wondered though those watches count too? I always told myself no. A couple of my birthday presents to friends have been momentum watches and I mean.. they're still alive. And they looked like they liked my present at the time they received it. Besides.. Who cares about curses or beliefs anyways?