Black hair? Blond or red? What color you like more and why?

I saw so many persons who like to change theirs hair color, and i wonder why?
In my opinion we must to be as we are in real, of course we can use a special shampoo to improve our natural color of hair, but must to keep our natural color.
Because is very simple to explain, a blond person will be not so beatiful id colored hair in black, skin all the time is in order with hair, and a very white skin will never look very nice with a black hair, or somebody with brown skin will be not natural with blond hair. Of course that contrasts are intersting, i mean black hair with blue eyes, or blond hair with black eyes, but all time our natural skin will be not nice with other hair color.
What opinion do you have about this?
If you want your change your hair color, what color you will choice?
I will say that i never change my hair color all my life, even i use a shampoo to improve my natural color, make hair to shine.