It may seem like a no-brainer, but friendship requires some flexibility. As the old proverb goes, "One who looks for a friend without faults will find none." While we all know it can be unrealistic to expect our friend to be faultless, sometime even our best friend may exhibit behavior which we find hard to swallow. If this continues, the friendship can become toxic, and the relationship is poisoned by bad feeling. Here are ways you can handle two kind of toxic friends.