Tails and personality

Question
I am trying to decide what breed of dog to buy.  I do not want a heavy shedding bread and I want an obedient dog. Everything points me to a Great Dane.  I am concerned about the tails.  A friend tells me they could be dangerous.  Could you dock the tail on a Great Danes?  Any other tips on Great Danes, good and bad?

Answer
A Great Dane is not for you.  The tail is part of the breed and they shed hair like it's going out of fashion.  We get half a vacuum cleaner full of hair every day from our house dogs.  

They are also head-strong and only obey commands when they can see the point of it.

You need something like a border collie.