Why is it that we feel happiness when we acquire the object of our desire? Reflect upon it! Is there any inherent joy in the object? We know intuitively, there is no inherent joy in the object. The same object is source of joy as well as repulsion for different persons. Then, where does this joy come from?
So, let us examine what is the difference between our position before and after the acquisition of desired object. It is not very difficult to understand that prior to acquisition, we are mentally agitated and we are quieter mentally after acquisition.
In the temporary quietude of mind, we feel happiness. We basically feel a trace of Self in quietude of mind. It is not that the mind can be made quiet only by accomplishing the objects of desire. There are other methods also, viz. meditation. In the absence of functioning of mind and intellect, only Self shall remain and there shall be nothing but bliss.