I so agree with you there, and more – assume one has reached the 100% fulfillment of ALL of one's Wishes, Hopes and Dreams. WHAT THEN?? I mean, it's the end of the line; passenger requested to leave the train of Life… so, Best is ALWAYS to have something MORE to strive for, so that the point of living&achieving shall NEVER come to an end.
From the same reason, we must NEVER expect Life, or ANYTHING in it, to be "perfect", as a term for satisfied Happiness… I once wrote a short Story, about a time in the distant future of humanity, when everything is perfect – and people behave perfectly, simply because they forgot, it is at all possible not to… and everyone just does their part automatically, being naturally perfect – but there is no joy in that and, in fact, when the emperor of the universe thinks about it, he becomes miserable beyond belief… as this is it, EVERYTHING HAS ALREADY BEEN ACHIEVED. And there is absolutely NOTHING more to ever strive for, in the entire universe… my saddest Story, in fact.
For me, the term "Happiness" refers, more than anything, to times in my Life, when I had the largest number, so to speak, of fully satisfying moments (even though they were not without background life-problems, as always), such as being One with Nature in a Forest, achieving Excellence in translating a Poem, teaching ❤ , or simply sittin'n'chillin', in a favourite Café, or by the Sea… 🙂 So, the eras, which consist of the most such moments, for me (July-September 2016, April-May 2018…) are Happy Times indeed. 🙂