Quote33. The cry of the flesh is not to be hungry, thirsty, or cold; for he who is free of these and is confident of remain so might vie even with Zeus for happiness.
I cite this passage because the words "confident to remain so" seems to me to be the crucial distinguishing factor between pleasure and happiness. I liked the way Cassius formulated it; pleasure is a direct feeling, happiness is a higher level construction that involves pleasure, but the hope of continued pleasure and the absence of fear.
Epicurus' core teaching about death is that it is "nothing" to us. This is essential. If what awaited us beyond the grave was eternal torment, no amount or length of pleasure would be adequate to keep us happy. We have to know where we're 'going' with it, in our life and after it.