The problem is 99% of people dont have enough money so they dont know.
Not quite right. It's not money that makes us happy, but what we can buy for them.
Money buys options and having more options is more likely to make you happy, or at least give you an illusion of control, which reduces stress.
I think what's more troubling is not that people feel they need money to be happy but the negative attitudes people have towards money. Poor people, who believe money would make them happier, tend to despise those who are more well-off, making themselves believe that those people just happened to be lucky, or have an unfair advantage, or doing something evil to become rich. This attitude then stop people from becoming rich themselves.
I also used to feel that way, though it changed a bit when I read some of Steve Siebold's books. Still not happy with my financial situation but at least I'm no longer sour-graping at the rich.