I wondered that too. I gave my score as 11 but then doubted myself when someone said else said they didn't have good health because they were overweight. I am too but I suppose I was thinking of "good health" meaning I'm mobile, can do the things I want to do, don't need any medication, feel well etc etc.
I am an optimistic person and also very laid back. I like the simple things e.g. I have time for hobbies but my hobbies are reading, doing crosswords and going for a walk!
Some of these things are definitely luck. I was fortunate to be born into a loving family, to have good health (but I'm aware that could change at any moment) and to have been able to have my DDs.
Some of it is judgement. I married the quiet, geeky, kind boy I met at University who has turned out to be the absolute best husband and life partner and now earns very well so money isn't an issue etc.
A lot of it is mindset. Looking on the bright side and appreciating what you have. But I'm fully aware I say this from a position of being very lucky, and that other people have a harder path.