But can it not ALSO be used in a way that is entirely positive and pleasurable, in which the pleasure of anticipation and preparation for the experience are every bit as enjoyable as the experience itself?
Cassius I agree that 'desire' is one of our important natural feelings that can help us achieve some of our most important goals or missions in life [telos] . My understanding of studying nature is that life is to create and re-create. Our body’s cells are being re-created all the time. Most people have a natural desire to make things (e.g. create something that improves their happiness) that didn’t exist, but now exists. Looking to nature shows how plants and animals are creating new life and contributing to other plants and animals.
I find in the Letter to Menoeceus, Epicurus states:
"We must also reflect that of desires some are natural, others are groundless; and that of the natural some are necessary as well as natural, and some natural only. And of the necessary desires some are necessary if we are to be happy, some if the body is to be rid of uneasiness, some if we are even to live."