Here is where I’d incorporate a time preference analysis, and use it to clearly define what you mean by “happy.” Or more precisely, when. Is it different from pleasure? You got into some first-person epistemology/introspection about memories and anticipations, which hints at a time preference analysis, but it didn’t go all the way there.
We can sort of look at usage: “pleasure” is usually used to refer to a momentarily pleasant sensation, whereas if I am “happy that I have X” I am thinking in terms of gladness that I will be able to experience the pleasures of X in the future. The more we expect to get pleasure from something (or someone) consistently in the future, the more we want to use the word “happiness.” This ties in with your/Mises’s points about uncertainty.
That’s one way, but an equally if not more important way is to be a winner. If you mention one it seems lopsided not to mention the other. Get rid of superfluous desires, yes, but also go after the really fruitful ones and learn to kick ass at it.
What are the fruitful desires, the ones that keep on giving? For this, I believe we need a way of coherently talking about what is “natural” and what is “unnatural.”* In terms of evolutionary psychology, natural generally means “what we are evolved for” or in this context, “what we are evolved to enjoy.” Rand seemed to sweep the complexity of this question (see asterisk below) away by using the word “life” instead. Forgive the lewd example, but someone thinking in that vein might say, “Anal sex is immoral because normal genital sex is where it’s at in terms of survival, reproduction, and life in general.” I would say that they are confusing themselves with words into thinking the problem is cleaner than it is. It seems a lot clearer to say that anal sex is probably not what you’re evolved to get pleasure from, especially in the overall context of the relationship. So although it may be more pleasurable in the short run, there is a lot less “fun” that could be had with the anus that with the vagina, long term, if you would just choose to curb your anal lust. I’m not saying this is true or not, but I’m trying to give an example of two purely pleasurable activities the pursuit of which might result in different long-term happiness levels. I didn’t choose junk food versus proper food, because that is more an issue of time preference.
I’m trying to make a more subtle point than that: that even in the case of unmitigated pleasures, one could still be more fruitful in a “gift that keeps on giving” sense. You want to cultivate desires for gifts that keep on giving, and not for those that fizzle out quickly. However, this could be different for different people, and it’s a game of prediction. One person might choose to cultivate a taste for classical music over pop since they believe it could make them happier for longer and in a deeper way, whereas another person might do the opposite because they argue that there is a limited pool of classical music that will eventually run out if you listen too much. A third person may argue that listening to music is ultimately (there’s time preference again) a waste of time, because it gives you direct pleasure without netting you much of any benefit “in the real world” (read: not much benefit for the rest of your activities and rest of your life).
In the modern world, since we are so far removed from the environment we are evolved for, a huge part of getting consistent long-term pleasure (=happiness) consists in solving the “indicator problems” (as I. Ryan termed them). An indicator problem is a problem in which the you desire something even though it would be bad for you, like a donut. The idea is that the environment for which we are evolved, our desires would usually align pretty well with what was actually good for us (desire for sweet foods would correspond to the rare chance to eat very healthy fruits, etc.).
*Natural (adj.) - of or pertaining to [the result or product of] a long history of intense competition on a rich marketplace (in the metaphorical sense where applicable), culminating in a highly interconnected matrix of symbiotic, win-win relationships or interactions. Details here: https://forum.freecapitalists.org/t/douglas-hofstatder-hayek-and-emergent-order/14288
Inaction just is pleasure, just is ataraxia. The reason I say this is that action is only wishing.
Suppose I wish to tear a receipt in half. I imagine it being torn in half, imagine a movie of me doing it, feel pain because it’s not done yet, and then my body merely follows suit. But that last part - the actual physical action - is only incidental. Movement in the physical world has nothing to do with action from a first-person epistemological (“I could be a brain-in-a-vat,” “this could all be a dream”) perspective. Wishing itself is what action is, and wishing is equivalent to desire (pain at some state of affairs not obtaining), which just is what action is. The moment you desired it, the action has happened. The rest is incidental.
When you stop desiring - always momentarily - that is pleasure. No desire at this moment = no action at this moment = no wishing at this moment = no pain at this one little tiny moment. You could feel pain interspersed timewise with pleasure, but on a finer timescale there is no mixing, no concurrent pain and pleasure in one moment, any more than there is concurrent action and inaction in one moment.
Mises sort of got this when he noted that wishing is action, but I don’t know that he made the full connection. Also, to treat one objection I initially had to this, “Can’t one feel pain without wishing for anything?” As a result of deep introspection, I do not think so. Pain just is the desire for a different state of affairs. If you can pull off the mental ninjutsu to see the electric blue bolts of pain streaking through you due to the dentist’s drill as just fun light shows, you don’t feel the pain anymore. Not only is all pain desire/wishing, all desire/wishing is pain. And desire/wishing just is action in the praxeological sense.
For pleasure, mutatis mutandis. Altogether:
Action=pain=wishing=desire. Inaction = pleasure = no wishing = no desire = (short-term) ataraxia. This makes sense evolutionarily as well, but that is unnecessary support because this is true as a matter of definition. It is just clarifying terms to dissolve some away.