The process of forming a desire can be rather complex and oftentimes involves numerous details that may cloud your vision in a way that prevents you from fully enjoying the idea of that which is desired. For instance, as a desire is formed, it may be the result of exposure to contrasting situations that are contradictory to that which is desired.
If such thoughts remain in your conscious mind as you attempt to manifest your desire though, you will find yourself being constantly contradicted by your own thoughts which in turn will prevent your energy value from matching the desire's fulfillment. This scenario is easily prevented though since you can completely purify your vibration by only focusing on the degree of happiness you want to experience, the degree of happiness that would be experienced were your desire to manifest.
It is the energy value of this particular degree of happiness that equals the energy value of your desire's manifestation. Thus, as you focus upon this state of happiness in its purest possible form, the way in which you would experience it were your desire to manifest, you will then quickly become aligned with the energy value of your desire and your reality will then change to match.