A good friend will let you fail...

Sometimes being a friend means mastering the art of timing. There is a time for silence. A time to let go and allow people to hurl themselves into their own destiny. And a time to prepare to pick up the pieces when it's all over. - Octavia Butler

http://www.brainyquote.com/quotes/quotes/o/octaviabut170210.html#47VW3mirbjgFUDb2.99

Sometimes for me I will not learn something until I fail. When I mean fail I'm really fail, face plant into concrete fail. For me it's very hard  to see my family and friends fail. You keep begging them to stop, to just listen, because its for their own good. You wonder how the hell do they not realize what they're doing to themselves, loved ones, and you. The fact is some people will not get it till it's too late, till they get that DUI, till they go to jail, till they brake their leg, till they hit rock bottom, or even worse they won't and unfortunately will pass away.
And you wonder "How can I just sit back and watch?" Reading this quote about friendship from Octavia Butler is very truthful. You must know how to react to the different situations they're put in. Especially when they hit rock bottom. A true friend doesn't hang around only at your prime, but stays with you, at your lowest point. They take a seat with you when you throw the biggest party in high school, and the cops come to bust it.