I don't know if I agree with that. Just because those things don't make you happy doesn't mean there aren't other things you can do with money that make you happy. Or maybe I just haven't matured enough yet?
At least I think I am at the point I don't care too much about having a fancy car or nice house.
Still, the thing that I have found to increase my happiness the most is giving it to someone else and seeing someone be really grateful. If I had more money I could do the same thing but to more people probably.
And probably just knowing that I have enough money that I don't need to worry would increase my happiness significantly. Even better would be that my parents don't have to work.
Well, that's not money then, that's helping others. One can help other people with no or little money too.
Also, "significant amount of money" is terribly subjective. I know people to whom $100 is a significant amount of money.
Depends on the persons age and maturity level too. At some point shiny new cars and other trinkets are not really what makes you happy...
Besides, if you're making a wage (whether way above average or not) you might not still be quite that independent that more money makes no difference (or draw your happiness from competing in the race)...