I remember one particular declaration concerning the idea that having money, substantial money ... requires the wisdom to spend it wisely.
I think there is a lot of truth to that. Sudden influxes of money, whether its from inheritance, sudden pro-sports contract or company buyout, reduces the perceived value of things. Material things are already subjected to Hedonistic Adaptation so the removal or moving of the value goalposts probably decreases your happiness at having those possessions and increases the desire to get more\replace those things that you thought you wanted so badly. Finally able to get that 65" TV you've been wanting for a while? Why should you be happy with that since they just released a 75" version that you 'now have money' to go out and buy? Keeping perspective and balancing needs and wants with a 30-50 year timeline for your balance sheet is probably not something many are prepared for.
Often there is an added time requirement to managing large sums of money and it can be substantial depending on the route you go or the situation you're handed. There can be an unforgiving learning curve when it comes to the law and taxes that many likely have not had to deal with before. Having a $2M inheritance isn't so fun when its mired in Probate or the Real Estate property located in another state is the subject of several frivolous lawsuits. Or writing a $50k tax check because the investments weren't handled in the most tax advantageous way. (Which is probably going to hurt a lot since they've not had time to adjust to a world where writing a $50k check isn't going to break them) Many see wealth as a way to remove financial headaches so the reality that it usually brings more headaches is a sobering experience and can quickly crush the happiness about the sudden influx - especially if you see large chunks suddenly flying away from your new bank account.
Certainly none of these are to the scale of 'trouble putting food' on the table or worries if you'll ever be retired which I think leads to another happiness issue: isolation. We're generally pretty social animals who like to share and talk about things but it can be hard to do that when others can't relate. "I bought stuff but it doesn't make me happy" can be tough to talk about when all everyone else sees is you driving the car they always wanted, buying all the high end tech gear they want but can't afford etc. You can say that true friends wouldn't care but you may not have known your friends have this ugly side till it shows up.