happiness is relative

What makes people happy? Is it purely based on what situation they are in right now?

How do you explain those people living in the cities in apartments, with more than enough food and water to sustain a balanced diet, with access to the internet and mobile phones, who are more down with life?
And compare these people to the islanders who only eat whatever the fuck they can find but are happy anyway?

It's all about frames of reference, and if you do physics, this would help a lot.

Now when people say they have a "need for speed", I find this quite inaccurate. They actually have a "need for acceleration". There is no thrill in travelling at a constant velocity of 100km/h. It feels just as thrilling as not travelling at all. Like, if you've sat on a subway before (hopefully a line that doesn't have many turns), there is no thrill of shooting around underground at 60km/h. Because travelling at a constant velocity exerts no force on the body, and hence you don't feel a thing.

Now the true thrill is when acceleration is experienced, ie when taking a sharp corner or when just straight out mashing the accelerator. The acceleration experienced by the body will cause the thrill.

Now I think the same works for happiness. An improvement in one's current situation will result in happiness. If one's situation is good for an extended period of time, it starts to "travel at a constant velocity", and hence they feel nothing. They can feel satisfied, but it's much harder to feel happy.

What you need to feel happy is a massive change in perspective or frame of reference. Going on AFX was just the thing for me. We lived in hootchies (click to see a pic of one that looks much like the one I set up myself), lived on ration packs for 7 days, constantly got rained on and blown around by the wind, had to deal with pricky officers (I did, at least - Brian had cool officers =C). We didn't have any resources to wash clothes, bodies, or even properly wash our hands. We also had to constantly work to keep our cadets happy despite all this.

This was my frame of reference. And now here's the "acceleration".

Brian and I, on the last day of AFX, when battalion allowed us to chill and sleep with our own home units, set up a hootchie that was spacious (ie, large enough so we could comfortably sit up in). We ate a dinner portion about twice of what the meal plan suggests, and I had a can of Sprite. We brushed our teeth properly and took a dump.
We were, after 6 days, in contact with other Ruse kids. We could do whatever the fuck we liked for about 4 hours.

To us, that was luxury.

Reflecting on this, it's actually in quite poor conditions on the grand scale of things. We weren't clean, we were in a fucking tent (no matter how big), we only had dying torches and glowsticks, we had to walk about 300m to the toilet. But we were smug as hell and happy beyond belief. It's not because we were good on the grand scale of things. But the improvement in conditions was what made it so enjoyable.

So the analogy is:
Where almost dying is 0km/h
Where living in a small hootchie etc etc on the first 6 days of AFX was 20km/h.
Where the last day of AFX with larger hootchie and taking a dump, brushing teeth, etc was 40km/h.
And most of our current living conditions with ample access to running water, internet, etc is 80km/h

Most of us are cruising at 80km/h, and we don't feel a thing. Because a constant velocity has no thrill, and it actually feels the same as sitting in the same place. Now us cadets quickly decelerated to 20km/h (which was thrilling nonetheless, as deceleration is just negative acceleration). While this deceleration didn't make us happy, it did make us somewhat excited. So we cruised at 20km/h, feeling alright but not overjoyed, and when the speed bumped up to 25km/h (the sun was out YAY), there was distinct happiness. Then on the last day, we were bumped up to 40km/h very quickly, and that was a massive moment of joy (as happiness and acceleration are directly analogous).

The stop by McDonald's was a bump for the cadets up to 60km/h (but for Brian and me it was terrible because we weren't meant to stop), but you can tell how happy they were for the unexpected change in situation in such a short time.

So an increase in situation is analogous to an increase in velocity. And so acceleration is analogous to happiness.

Mathematically, if you differentiate distance (strictly displacement) wrt time, you get velocity. If you differentiate wrt time again, you get acceleration.
Similarly if you integrate acceleration wrt time, you get velocity, integrate again and you get displacement.
Now there is no suitable analogy for distance (situation is measured wrt time as well!), but velocity can be analogous to one's situation. If you differentiate the situation wrt time, you get happiness.
Similarly if you integrate the measure of happiness wrt time, you get the situation,

Hence happiness is defined by the measure of change in situation over time.