Hedonism is celebration of life that humans live only once, by filling every second with maximum happiness, where only what is pleasant or has pleasant consequences is intrinsically good, as philosophers define hedonism.
The principles of hedonism help us always remember the chief purpose of life—happiness—that all other purposes, philosophies and endeavors must lead to. It provides ways to maximize ecstasy and discover new pleasure sources satisfying our endless "insatiable" desires—as hedonism and curiosity go together, to avoid repeating oneself and regressing to animals' rank.
Unlike body hedonism, mind hedonism or the thirst for knowledge can never be fully quenched, as no one can hold the truth that one can only come closer to. Honing one's "sense of hedonism" requires constant alertness for new pleasures, knowing that the mind's primary function is to serve that instinctive hedonism most animals have, in a sophisticated manner only unique to humans.
No one wants to spend their brief conscious existence in pain, or lose a single moment to pain, as it's always a possibility Death meets you at that very moment. Hedonism gives meaning to the short mercurial human life, as the ONLY firm ground to stand on in the face of life's turns:
The Paradox of Hedonism
Some philosophers believed hedonism contradicts duty, sympathy, seeking the truth, or even "seeking happiness": failing to be happy when you want to be happy, i.e. the paradox of hedonism. Misunderstanding pleasure chemistry, while impressed by the partial temporary appeal of pain, they missed the whole picture. Their subjective incomplete definition of happiness has led to the misconception of hedonism.
Mill, Nietzsche, and many philosophers had views of hedonism influenced by their age, before the advancement of neuroscience showing the release of endorphins DURING many physical, intellectual and social activities, refuting the paradox of hedonism advocated by such philosophers, who believed we can't enjoy what we desire simultaneously; we can't think of it then; and even we can't think at all when we are really happy. That is untrue for many reasons.
Hedonism paradox only applies to some dopaminergic physical pleasures, that, like all instincts, are operated by the lower brain that naturally slows higher brain functions. Some pleasures, like food or sex, have a short immediate doping effect making thinking difficult; whereas others, like intellectual pleasures, taking longer to be felt, have a deeper longer effect without losing one's consciousness.
Only recently we could recognize the chemicals responsible for our pleasures, physical, intellectual, or involving both body and mind, where we can simultaneously think and move, look, hear, etc. Thinking gives intensity, durability, diversity, and security to many sensual pleasures. Claiming that thinking decreases or disrupts pleasure is like saying you can't enjoy an apple while chewing it, sight-seeing while your eyes are moving, or having sex with any part of you moving.
Filling every moment of life with happiness is not paradoxical, it is only incremental, for there is always room in the smallest time units making up the entire human lifespan, that humanity is yet to enjoy properly and deservingly.