You have 5 seconds to choose your future: Winning a 20 million lottery ticket or getting yourself paraplegic (not forever, you could get to walk again after some years of treatment).
While it sounds very stupid and obvious, your brain would not feel much difference. Of course, the first impression on getting rich would be far better than getting your legs useless for a while. But after like a year, the overall status of hapiness on you brain would get back to normal levels.
If we focus only on hapiness levels, the paraplegic chooser could have a little advantage when looking in a bigger time frame.
Hapiness almost never increases when we are static. The action, the movement (no pun with the crippled guy here), the changes, all of that impacts on our levels of hapiness. The rich of course would have the option to get new stuffs, know lots of place, use the money increase his fortune and see tons of action. As could the paraplegic gets into some state of deep depression and refuse to fight for himself, but the odds are that the lottery guy would focus all his emotion on the "I WIN" fact and the paraplegic in the process of getting to walk again. And as mind is always more sensitive to changes than absolute levels, the later process is a plate full of oportunity to increase his overall hapiness (of course, it is always linked to determination and willpower, as it can also be a sour cup of depression oportunities)
We can now wonder why capitalism always bombs out our minds into changing our stuffs and why it is like "meh, ok" a little after we get used to the new toy, car, dress, house and always excited when saving the pennies to get what we want.
It is all about how our mind works.