The euphoria you describe (a big party with friends / dancing / singing / drinking) is a form of suffering experienced by samsaric mind. If we look very carefully deep into ourselves we can see how even within so-called pleasant experience there is a seed of unsatisfactoriness. There is always this anticipation of hangover, or feeling that we're missing even bigger fun, or timidity and up-tightness etc. This is due to an element of confusion inevitably present in a non-enlightened mind.
In Buddhism, happiness (sukha
) is different. There are two kinds of happiness: worldly happiness and happiness of sugatas.
Worldly happiness is a quiet feeling of ease and comfort we experience when our existence is not burdened by troubles and emergencies. This is achieved by following common guidelines for good living, first and foremost the five precepts.
Happiness of sugatas is suchness (tathata
) rooted in Final Knowledge, transcending all dualities such as desirable/undesirable. This is achieved by following preliminary guidelines for trainingtaming the mind, the special guidelines for gradually reducing the clinging, and the secret guidelines for attaining the view of spontaneously self-existing great natural perfection.