Riddle for Life

I am your constant companion.
I am your greatest helper or heaviest burden.
I will push you onward or drag you down to failure.
I am completely at your command.
Half the things you do might justa as well turn over to me and I will do them-
quickly and correctly.
I am easily managed - you must be firm with me.
Show me exactly how you want something done and, after a few lessons, I will do it automatically.
i am the servant of all great people; and, alas, of all failures as well.
Those who are great, I have made great.
Those who are failures, I have made failures.
I am not a machine, though I work with all the
precision of a machine, plus the intelligence of a person.
You may run me for profit or run me for ruin-
it makes no difference to me.
Take me, train me,be firm with me, and I will place the world at your feet.
Be easy with me and I will distroy you.
Who am I?
I am Habit!
-What they don't teach you in Sales 101