He said: "When you chose to be a friend with someone, you also chose to be a friend with his/her traits, both good and bad. This means that you have to love him/her for the way they are. If your friend has bad traits, tell them about it and remind them to fix it. That’s how a good friend should act."
I remember his words every now and then and I'm glad that he told me this. His words make me cherish my friendships with all of my friends and I think that’s also one of the reasons that I have strong bonds with my friends.