Success and requires climbing a new peak

Why no one feels pleasure continuously? Maybe people "get tired" of happiness? Just a man accustomed to his achievements, success and requires climbing a new peak, there is a need for deeper experiences, different self-affirmation and spiritual enrichment, which disappears without a sense of fullness of being. (L. A. Popov Ethics. A course of lectures. - M., 1998. - P. 79). Besides, nothing human is capable of continuous operation. No wonder Aristotle associated the pleasure with the activity.
"Pleasure is not continuous, for it accompanies activity. Some things I enjoy, while Nova, and then not, and for the same reason, the first thought is passionate and intensely active in, for example, when the faces, but after the activity is not so strained, on the contrary, she is often careless, but because they fade and pleasure.
It can be assumed that all strive for pleasure for the same reason all are drawn to life, because life is a kind of activity, and each operates in such areas and in such ways, what he especially Luba; for example, the musician works by hearing the tunes, curious - thought in the objects of speculation, and among others to behave towards each. Pleasure gives the perfection of the operations, and hence of life itself, to which all aspire. Therefore, it is clear that and are drawn to pleasure, for everyone it makes life complete". (Aristotle. Vol. in 4 vols. Vol. 4. - M., 1984. - S. 275).
However, most of those people who brings happiness to pleasure, thanks to common sense understand that happiness in special treats: long associated with the serenity and joy of life. Therefore, many devote their entire lives to the search for increasingly refined pleasures, trying to prolong an illusory happiness in this way.