this keeps us motivated, it's like a fuel that keep pushing us; either forward or backwards,
some people might say that anger will pull you backwards while love will push you forward, well not true, not always anyway.
but the real problem is when you run low on both types of fuel ( love and anger)
this is when you start slowing down and loosing the power that kept you moving.
it's at that time that you start feeling like a zombie;
you're not the living you
and there is no reason for you to die
so you live like a zombie, half alive half dead, motivation lost , anger fading away, and no more hopes or dreams can find their way into your brain on heart anymore, simply because you have no energy to keep dreaming and no motivation to keep you hoping.