"choose your friends wisely".

I learned that not everyone can or is your friend(s). and the people or person you think is your friend(s) could be the people that's really trying to put you in a bad mood because you are doing way better than them in life so they will think of something that can always make you angry without you knowing that they were or are behind your anger until you sit back and really think about who your real friends. so choose your friends wisely and try as hard as you can to keep drama as far away as possible.

http://christianteens.about.com/bio/Kelli-Mahoney-22612.htm

Think you don't get to just choose who you're friends with? Absolutely not. You get just as much say who your friends are as they do. Making friends is one thing, but choosing who your friends are is incredibly important, because your friends are your guides in life as well as the people who help define who you are. In some ways, they are family. There are some friends who are closer to you than others, but who you choose to share important parts of your life with matters.

Choose a Friend Who is Honest

A friend that is honest is one of the best friends you can have. Trust and honesty are cornerstones in any relationship. Choosing a friend who can tell you how it is will be something you'll appreciate greatly (albeit, you may not always appreciate it in that particular moment, you'll look back on it and appreciate it later...really). An honest friend will keep you from walking out of the house wearing that awful green shirt or tell you that the girl you're going to ask out isn't interested. They're supportive in their honesty, and you should choose someone you know will not lie.