Anytime this question comes up, I always think of the guy in the black cowboy hat from a decade or so ago that won the lottery big.  He was a generous outgoing guy who tried to spread it around, but a year later the news had a story about how unhappy he was.  One sentence sticks in my mind.  They said, "his daughter lost all her friends." 

I can see that happening.  One friend asks for help with some urgent expense so the daughter of the rich guy gladly helps out. Then another sees that and asks for money for a slightly less urgent thing and pretty soon they're all demanding money because she gave some to someone else.

In fact, I've seen surveys of lottery winners that indicate most are much less happy after a while.

I never buy lottery tickets, partially because they're a mechanism of government corruption, partially because they are a tax on stupidity (the more stupid you are, the more you pay), and partially because I don't want to win it big and be unhappy.