Most personal enemies start out as friends, or apparent friends.

When you treat someone as a friend, it makes you vulnerable, because:

• People you’re close to know things about how your mind works that they can use to manipulate you
• Friends count on each other to actively treat one another well. If you count on someone and they aren’t actually trustworthy, you get hurt
• Friends give each other the benefit of the doubt. If you give someone the benefit of the doubt and they don’t actually mean well, this gives them a large opening to do you harm.

It also means they know private things about you that they can use against you if they decide to be your enemy, and that people who perceive them as close to you might trust their opinion.

Sometimes you shouldn’t give people a chance to get close to you. Sometimes it’s not a good idea to allow yourself to become vulnerable in that way.

Not everyone is a good friend.

I wish I had known this sooner.