Every art and every inquiry and similarly every action and choice is thought to aim at some good and for this reason the good has rightly been declared to be that at which all things aim.
I think happiness comes from self-acceptance. We all try different things and we find some comfortable sense of who we are. We look at our parents and learn and grow and move on. We change.
If you just watch a teenager you see a lot of uncertainty.
You do have to change things as warfare changes.