Because promising ALWAYS is never in your control. You are well-intentioned to be sure but the road to HE** is paved with good intentions.
Same with NEVER. You say "I will NEVER lie to you". Then you do. Oops did you forget? You promised NEVER and then you lied. Why? To cover your butt for doing what you wanted to do no matter what.
So while ALWAYS and NEVER are so noble and heroic they really are meaningless in the real world.
Unless you can always control what you encounter in life and always know how it will end there is no way you can ALWAYS or NEVER with absolute assurance you will keep your word.
