I am your constant companion

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 just as well turn over to me
and I will be able to do them quickly and correctly.

I am easily managed -
you must merely 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 human.
You may run me for a 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 destroy you.

WHO AM I?


I AM HABIT.