How does one choose good friends and filter out the people who tend to fuck others over?

I ask this because I have read comics etc about this and personally experienced the following:

" Dated a girl, best friend since childhood steals her away. "

I also have run into those that are going to steal things, won't pay you back, break plans often but then complain when you even talk about breaking plans with them, etc.

  • How do you sedditors obtain and maintain friendships that are healthy strong friendships?

  • Are there a set of rules you have when it comes to friends like, "don't loan them more than 20 dollars" or (not sure about this one) "Don't let them be around your gf without you around" (by that last one i mean close guy friends not just random guys because that doesn't seem to matter)?


Current good points made:

  • Don't mix business with friendships unless you are ok with not being friends anymore
  • If you are going to loan money to a friend, consider it gone and be happy if you ever get it back
  • Don't loan out books, you probably won't get them back
  • Not everyone can be a confidant, filter heavily when it comes to those who come into your inner circle
  • Watch how they treat others, they will treat you the same way
  • Do they steal from others? They will steal from you as well.
  • Are they willing to lie, cheat and steal? They will do it to you as well. You are not an exception.