Self-actualized:
…ahem…
I’m good enough. I’m smart enough. And goddammit, people like me!
It means that you’ve reached the biggest goals of your life and it’s different for each individual. Some want to win an Oscar or earn a million dollars by age 40 or live in another country or get a pilot’s license or become a prima ballerina or whatever. But the lower goals like food, shelter, safety can’t be brushed aside…when those are threatened the higher ones have to take a back seat. So we move up and down the pyramid.
If you reach a major goal, the rush is immense. But the feeling only lasts so long. Someone like Steve Jobs kept plugging away.
https://www.investors.com/news/technology/top-10-steve-jobs-achievements/
His achievements were clustered around technology but maybe others would have a variety of goals for the bucket list.
The rise of the middle class allowed people time to reflect. I assume 200 years ago most people worked like dogs and had little energy or time to question whether they were happy or fulfilled. It’s a double-edged sword for sure. I think the New Yorker had the cartoon where one guy says to his friend, “I’ve got a great career, tons of dear friends, a fantastic family, an incredible future, exciting plans for the future, a meaningful relationship with God but…I don’t know, something’s missing.” 
Accepting and understanding your own internal wants, needs, strengths and weaknesses and building a life that accurately reflects those.