This is a serious topic, not one of my joke topics.
I begin by asking a series of questions, and answering some of them, either with questions or other answers. Most of the answers you'll just have to accept, some of them are debates in themselves, but that is not the point.
Q: What do I like / want?
A: Stuff.
Q: Why is that?
A: Because during the course of my life I have made associations between what I like now and being happy.
Q: And what caused you to make those associations?
A: For most of them, they actually make me happy, or I have reasoned that they would make me happy.
Q: What about doing things just for the satisfaction of doing them?
A: Satisfaction is a form of happiness. It's just an arbitrary distinction.
Q: Who made that distinction?
A: People did.
Q: And why did people make that distinction?
A: Because it is satisfying to do so. They like it. It made them happy.
Q: So why do you want to do things that would make me happy?
A: Because I like to be happy.
Q: But why do you like to be happy?
A: Because if I didn't like being happy, I would avoid being happy, and if I succeeded in avoiding being happy, I would have avoided what I didn't like, and then I would have gotten what I wanted, which is to be unhappy, and getting what I want makes me happy.
Q: How is being happy a good thing?
A: It feels good.
Q: So desiring happiness leads to happiness, but desiring unhappiness is paradoxical, because you are happy that you have made yourself unhappy, and unhappy that you have made yourself happy. What desire would lead to permanent unhappiness and dissatisfcation then?
A: Idunno, maybe wanting to be sort of happy.
Q: Are you sure?
A: Well, if I want to be sort of happy, and I become sort of happy, then I am happy, but then I am unhappy because I am not precisely sort-of-happy. On the average, I become sort of happy, though, which makes me happy. So I suppose as time passed on it would either continue alternating or would approach happiness.
Q: So no desire being fulfilled will lead to definite (non-paradoxical) unhappiness. Are you saying that desires are associated with happiness and satisfaction?
A: Well, duh.
Q: Okay, that's a fair statement. What if we had no desires, then?
A: Well, I suppose if you don't want to have or not have anything, nothing will make you happy or unhappy.
Q: What about some outside influence making you happy?
A: Well, then we're talking about something like physical pleasure.
Q: But what if you desire not to have physical pleasure? Like if you're a monk or something?
A: If that's the case, you have a desire, a desire to avoid physical pleasure, and by doing so you are satisfying that desire, which is a good feeling.
Q: And is a "good feeling" "pleasurable?"
A: I guess.
Q: Then what if you have no sense of pleasure or displeasure? Would you still have desires?
A: I doubt it. I mean, there would be no motive.
Q: Would anything ever get done?
A: Not intelligently, no. I mean, you wouldn't even want to experiment to figure out what you are capable of doing. Sure, actions could be done on you, and you would be affected by them, but effectively you'd be a rock.
Q: So then, in individuals, there is a self perpetuating cycle?
A: Sure, that makes sense.
Q: But where does it start?
A: Well, if you buy into the creationist theory, then the first man had desires of some sort.
Q: And how did it get passed on?
A: Well, he obviously had the desire to reproduce, because he did so.
Q: And where did that desrie come from?
A: He must have been created with it?
Q: Okay, what if I don't buy into the creation theory? What does "evolution" say?
A: Then it started by some random fluke. I guess it is also possible that it was started by some outside intervention, but after that, the laws of nature were in charge.
Q: But what could be pleasurable to a molecule of DNA?
A: Nothing, it doesn't have a sense of pleasure.
Q: Then how can evolution work?
A: Well, it seems more like it would have been a combination of many smaller flukes, each individually of medium-low probability, but being possible in many many places for a long time. Eventually, it was bound to happen.
Q: What if it didn't happen?
A: Then we wouldn't be here.
Q: But don't you like being here?
A: Well, I do, but if I didn't exist there would never have been a me to complain. Come to think of it, if life had never formed, there wouldn't be any happiness or unhappiness, pleasure or displeasure, satisfaction or dissatisfaction, as a result of that lack of an event.
Q: So what's the point of doing what makes us happy if in the future if we don't do what makes us happy (following the instinct to perpetuate the species, in particular) nobody will be around to care?
A: Well, it makes us happy now, and it will make future generations happy.
Q: But if they aren't born, they won't mind not being happy, because they don't exist, and it's not like they're unhappy either. So how does it matter?
A: I suppose it doesn't, but I'm going to do it anyway.
Q: Why's that?
A: Because it's easier and more fun.
Q: And why do you want to do something that's easier or more fun?
A: Because that is the way my species is.
