Most of life is mundane, so many cannot be with the mundane side when it is around 98%. (Cleaning/finance/shopping/work)
Then transform the mundane, that is how you are being in each moment.
Then your mind is the key, if you dwell and mull over your mistakes, then you keep them in the forefront, not the past where they belong.
To be complete with the choices that you have made, be it, if they worked out or not. To be complete.....
Happy is a state of mind, it has nothing to do with your outside world (Money/home/car)