Enemies and easy to get and even easier to keep. But friends are hard to get and even harder to keep.

A friend is one who has the same enemies as you have

We are not enemies, but friends. We must not be enemies. Though passion may have strained, it must not break our bonds of affection. The mystic cords of memory will swell when again touched as surely they will be by the better angels of our nature.

Do I not destroy my enemies when I make them my friends?

The best way to destroy an enemy is to make him a friend.

Being smart means you learned it well; being stupid means you haven't learned it yet; but true genius means you know it when no one taught it to you.