Enemy is a beautiful concept. You never say he is an enemy,
but you always refer, he is MY ENEMY coz he is a part
of your EGO, coz when he dies, you never be the same person
as before. We spend most of time thinking about our enemies.
That's why its easy to miss your friend but not your enemy
on the road.

If you observe, you treat even beggar as your enemy,
you never see a beggar an eye to eye coz if you, then
he will become you friend and his problem become your problem. Generally, people with whom you grow... brother/cousins/neighbor,
they are the one, who carry a small jealous about you and
your growth. coz they know your capacity and often compare you
and your growth,  and they are the one always compete with you.

In Mahabharata,  Arjuna refuse to fight against his own cousins
Kauravas, The reason, he knows very well he can
defeat Kauravas and retrieve his kingdom. But what FUN you
have, once, all your are enemies are dead, there is no fun in ruling
the kingdom. We need enemies to move our life, we need people
around us to feel jealous, that's why we buy a big house,
costly interiors, a luxury Cars,.. etc  less for us and more for
our Circle. We want every one to feel small when they
enter our house.

The Box office hit movie are successful not because of the Hero
but coz of villain, the most cruel the villain,  then, he help the
movie more interesting and also to the success of the film.
In Short,  Its your enemy determine your success. The more enemy
you have, the more drive you have towards your success.