It's very easy to make enemys more easy than to make friends but there is a big diference between people you just don't like and enemy.
Enemy can appear everywhere in your work, neighbours etc but the real, worst enemy are the ones you were friend in the past.
How to make a real enemy?
It's very simple , you win the simpaty of the person and has closer the person is to you better it is. Then one day just do the most stupid thing in a world, doesn't matter the motive and hurt the person real bad, then moove on and leave her.
If everything works well this person that is still a bit surprise with your reaction will hate so much that makes them your perfect enemy.
To increase the bad fillings just ingnore the person and let time work.
I just want to say sorry to all my enemys and i just hope not increase the number has fast i am doing now.