The most regret of the life

Do you know what is the most regretful thing older people think?
One of the answers is below;

Huff Post: he Most Surprising Regret Of The Very Old -- And How You Can Avoid It

The author interviewed thousands of people to conclude that the most regretful thing was to worry about the future. Actually, a lot of older people said that too much worry wasted their real life, according to this article.

I agree with this partially. The future is unclear and the life is quite vulnerable. Abstract worrying is useless for the life. Saying that "I'm afraid of X" instead of worrying is a very suggestive tip in this article. I also use this technique in my psychotherapy.
However, this article has a big problem: a selective bias.
All of the people whom the author interviewed are older people. They survived their tough lives. If they had not worried so much what have occurred upon them? It is possible that people not worried so much passed away in younger age, isn't it?

It may be correct that too much worrying is harmful. Nevertheless we hardly avoid from worrying.

By the way, I will show another answer to the same question.

Inspiration and Chai: REGRETS OF THE DYING

The author of the blog is a nurse engaging in a palliative care in Australia. She listens to the patients nearly dying. And she has noticed that most people regret the fact that they had lived their own lives instead of others. "I wish I'd had the courage to live a life true to myself, not the life others expected of me."
It is also suggestive. The life is yours, absolutely. Many people could not understand this simple fact. Is it true? Is it so difficult to live my own life?
Human are social being. If most people lived only for oneself, the world would be more cruel. The balance between the self satisfaction and contribution to others is quite difficult. Based on the research of the author, most people may be too good.

Interestingly, a Japanese doctor wrote a book on the same theme.

Amazon.co.jp: The 25 regrets before the death (in Japanese)

The author is a physician whose specialty is palliative care.
His conclusion based on interviewing over 1,000 patients is that the most regret is not to express thankfulness for loved one.

It is the opposite of the result above.
Is it derived from the difference of cultures? Or some other bias made the difference?

More or less, we hardly avoid from regret.
At least, I will live my own life with the persons I respect for. It is what I truly hope.