A lot of contemporary models of human being suggest that we are basically 'directional'. What that means is that we are always 'going to somewhere', always pointed in particular directions. We're striving, trying to improve things, trying to be something and somewhere more than we are: even if it's more chilled out! If that's the case, then we can understand wellbeing in terms of how much we're able to 'actualise' this direction: how much we're aligned with where it is that we want to go.
This actualisation process can be understood in terms of six As. First there is awareness: knowing what our goals are and where we are trying to get to. Second there is anticipation: having a sense that our goals are possible and things that we can achieve. Third comes approach: progressing towards the things that we want; and then comes acceleration: moving towards our wants at an increasing speed. Importantly (but maybe not the most important thing) is then achieving our goals. Finally, and particularly one that may become more important with age, is appreciating what we have achieved.
So, viewed from this perspective, the 'good life' is one in which we have things in life we're striving towards which are important to us, and we have a sense that we're making some kind of progress towards them. We don't have to get these goals all the time, or move rapidly on to other things, but just a general sense that we're pointed in a direction and that we're able to attain it in some way. And from this perspective, psychological problems are associated with not being clear about what we want from life, or knowing what we want but feeling that it is impossible to get there--or not making any progress at all. Or even it might be about getting to our goals but then not taking the time to appreciate what we have achieved and just rushing on to the next one.
Last thing: if we think about wellbeing in this way, it also shows how what we feel is both about ourselves AND our social and political environment. I might not progress towards the things I want because I don't have good strategies for getting there. But I also might not progress towards the things that I want because the world is telling me about all these amazing things I should have (a perfect body, the latest phone, a devoted partner) and then not providing me with any possibility at all of getting there. So helping people change the way they go about things can be important--through therapy or self-development work--but what can also be really important is focusing on social and political change. If we create a fairer world with more resources for everyone, then more people can move towards more of what they want more of the time.