The concept of "generations" as defining peer groups is broken

In My Humble Opinion
61

This thread made me curious how other countries aside from the United States define the generations. I was going to ask here but decided to start my own thread since it is NOT what the OP asked about:

https://boards.straightdope.com/t/do-other-countries-use-baby-boomer-and-generation-x-or-what-do-they-describe-the-generations-as/1004914