"Albert Einstein Insanity: doing the same thing over and over again and expecting different results."
I was once told a story about actions, and their relations to sticks. Think of every action you make as the end of one stick. By picking up the end of a stick, you also pick up the other end, or the consequence. Not all consequences are bad. They're just the following event. The effect to your cause. But you can't pick up the top of one stick, and get the end of another. You will always receive the same effect for the same cause.
But people, me included, tend to believe that this will change. But we will always be let down by the fact that this is not the case. We will drive ourselves insane expecting different results. This is when we realize how trusting and forgiving we are. But we need to change that, or we're only hurting ourselves.
Don't expect the worst of people right off the bat, but don't keep forgiving someone if they've continually let you down. Don't be rude about it either, but just know that they're not the most trustworthy of people. Be kind to others, but not so kind that you start to hurt yourself. "...