I love this quote because it sums up beautifully one of the primary components of law of attraction. We must be what we want to attract. Happiness is not a destination, but a choice. When you choose to find peace and joy, more of the things that give you peace and joy will make their way into your life. The opposite is also true and becomes very apparent when we are stressed, angry, or otherwise upset.
Many of us give our power away. We believe on some level that life is a series of events that just happens and we have no influence over it whatsoever. That mindset can lead to self-sabotage. For example, have you ever woke up late only to panic and exclaim "I'm going to be late!" Feelings of powerlessness set in and suddenly you are anxious. As you stumble around, rushed, confused and full of anxiety, thoughts of the boss being angry or losing a chance at promotion start flooding your thoughts. Your anxiety level heightens and you are feeling these fears with great fervor.
As you run around in a panic, nothing goes smoothly. You lose your keys, struggle to get out of the door and the whole time you are feeling increasingly pressured, tense and anxious. You drive off only to realize you forgot something important and on your way, you are caught by every single traffic light. For no good reason, every slow driver in the free world manages to be in front of you. Your anxiety heightens even more and even more things begin to go awry. Why? Because you woke up in a panic and felt it with so much passion, that you continued to attract situations that fed that panic.
However, had you woke up late, but remained calm - you likely would have discovered that everything you needed was where it belonged, you didn't carelessly forget your items because you weren't distracted by feeling panicky and rushed. As you relaxed, things would once again flow smoothly and instead of being a half an hour late, running through the door already stressed and frazzled, you may find you walk in the door only a couple of minutes late (if at all), prepared with everything you need, and that no one really notices and you can go on about your day as normal.
If you resonated with the above scenario ;) and many of us have, chances are you are allowing your feelings to dictate your state of mind rather than consciously choosing where to place your thoughts and energy.
This quote is a reminder to condition your circumstances - rather than letting your circumstances control you. The one thing you always have the power to control is your mind. Condition your thoughts and your world will be transformed. This is the main focus of the Law of Attraction and also the Law of Vibration that states what you put forth energy wise is returned to you.