Because even if you achieve happiness there will be something that will bother you. It is in our human nature to look more at the bad sides than the good sides.
Money: a billionaire stills has problems avoiding taxes and losing all assets.
Early-pension: people need a purpose to do something, otherwise you will get bored.
One happy family: outside influences (boyfriend/girlfriend) can negatively influence you.
However it's not all bad, we just have to focus less on the negative sides and look to what we can achieve.
As a great though experiment start to write to yourself from there and then take on the personality of that person and respond.
What would they say to you? Obviously things go wrong in every universe so how does that alternate universe you mentally frame issues. What decisions do they make when faced with choice.
( trying this with bard led me to being a cyborg this made me like AI more and trust it less)