The same way we would 'spring clean' our homes, we should also take some time to spring clean our lives. Our minds can get cluttered with things we don't need, accumulated dust, disorganized dimensions, bad habits, and previously formed ideas and impressions that should be thrown away or at least reconsidered for accuracy and consistency.
Every one of us has been betrayed or let down in the past. A mentor passes away, a trusted co-worker moves onto another career opportunity, friends go in their separate directions. The only constant in the mathematical equation of life is you. The only thing you can control (and sometimes not even this) is you -- your behavior, your decisions, your actions.