Vain desire leads to short satisfaction
«Why does satisfaction last such a short amount of time?»
Because the desire satisfied was non-natural.
The nature of a vain desire is such that it cannot ever be truly fulfilled, unlike the necessary or natural desires. Therefore the desire returns quickly.
If you suffer from short satisfactions, you need to evaluate those desires thoroughly. What would happen if you didn’t satisfy this desire?
If the desire is a vain one, nothing bad will happen. You can safely and painlessly discard such desires to seek more stable satisfaction.
If the desire is a natural one, there might be some initial discomfort, but the positive results out-weigh the negatives. You can discard these desires, too, or you can occasionally indulge, but only carefully. These are dangerous desires, easy to over-indulge in…
It might turn out that the desire is a necessary one. Necessary for comfort, Happiness, or even to Life itself. In this case something is seriously wrong! You’ll need to seek expert advice. For example, if you’re always thirsty, and water doesn’t satisfy you, no matter the amount, you should go to the doctor. You might be sick.
Evaluation of one’s desires is a difficult task, but a necessary one. Without it we’d be at the mercy of our whimsies and vain opinions, and never truly Happy. But then again, nothing worthwhile is ever easy.