happier at 40+

this is the new paradigm amongst a lot of women i keep meeting these days...mostly on work, but with whom i tend to bond at a different level altogether... and all that we agree on is that we are far happier today than we were at 20+...
reasons? simple enough -- too much to prove, too much to achieve, too much to do then.
now? have proved some, don't care about the those that have not been proven; have achieved quite a bit, don't want to strive very much harder; have done quite a bit, don't care about the rest.
in a word, we have learnt to live life on our own terms... and that is what happiness is all about, isin't it?