Why are people so greedy? Why can't they wait to be given something, or remain content without, rather than take from others by force? I'm genuinely curious too.

Animalistic survival desires under conditions of engineered scarcity and reduced awareness. Compounded with powerful need for consistency - to keep everything this way.

Anyone with a decent amount of social power is aware and skilled at maintaining these conditions whether consciously or not.

The praxes are non-trivial: awareness, bravery, flexibility, and seflessness.

This could be summarized as "unhealthy competition."