I didn't think it was a Bangladesh tradition... I thought it was
a general rule. I'm a female and I've always put my watch on my
left hand and my dad has always put it on his right (we're
Australian). I've mainly put it on my left hand because I'm a right
hander so it gets in the way when it's on my right hand but if
you're ask this, you might as well ask why female shirt buttons are
on the left and male shirt buttons are on the right.