Should puppy dogs tails be docked??

I don't know that it is mean. I grew up on a farm and we used to dock cow's tails out of neccessity. I know it's hard to tell and that cows are not dogs, but it never seemed as though they were all that affected by it as far as pain/discomfort. When it comes to dogs though, I've never really seen the purpose in it. Of course I've never owned a breed that traditionally has its tail docked. I probably wouldn't do it just because it doesn't seem to me that it serves a purpose.