Of course, having enough money to live comfortably helps everyone be happy.
What I mean is if tomorrow you won the lottery, after the initial novelty wore off and you'd bought all the crazy shit you dream of, you wouldn't be any more happy than you would with enough of an income to live comfortably, and in fact might even be more miserable.
One big thing that happens to people who win the lottery, or their relatives, is drug overdoses. I'm gonna go ahead and guess that a member of this site who suddenly came into millions would spend a great deal of it on drugs. I'm pretty sure if I was that rich I'd OD from a Micheal Jackson level pharma combo within a month haha.
But it's not just about that. The novelty of having luxury shit will wear off quickly for you, but the idea of it won't for the people around you who will always want what you have. So how do you know your friends are hanging around because they like you or because they want something? Same even goes for family in many cases. And sure you will attract a lot of women, but the same question pops up... maybe no problem if all you want is sex, but if you want an actual relationship it's gonna be very hard. And all sorts of people (friends, family, whatever) will come to envy and resent you. Loneliness is one of the top causes of depression and suicide alone.
Honestly yeah I'd go on a mad shopping spree and buy a Bentley and some mad fancy London penthouse and be dressed in Gucci everything and line up a few of those dodgy private docs who will script anything for cash, but I'm not naive enough to think any of that would actually make me happy when the novelty disappears in a month and tolerance builds to the drugs just as quickly.
I've met rich people but never met one who could actually say their wealth made them happy. You do get rare, highly driven individuals who laser focus on something very specific and enjoy the
pursuit of wealth, but that's another thing entirely and they'd still say money itself won't make you happy.
Something probably more relatable to most people here, you ever quit doing a certain drug and suddenly find all your "friends" disappear? This is basically the same thing. Except you can always find new friends who ain't into drugs, but pretty much everyone will treat you differently if you are wealthy.
It's a more complex psychological effect than people tend to assume. Honestly, read up on some of the dark stories of lottery winners, it is (morbidly) interesting. There is also a good TV show they did a while back called Syndicate which is along these lines.