there ain't such thing as purpose of life.
you live, because you are.

its just circle of life.

your desire for something (food, love, achievement, etc) are just part of your instinct.
its good to set goals, but ultimately, the purpose of life is just to live.
there ain't no bad life or good life. its just life.

if you do bad things, it might hurt you with consequences, or it may not.
if you do good things, its the same.

what makes us humans differ to other animals, is that we think and decide whats good or bad.
but in the end, its all subjective matter, and you just live.