The person had it “too easy” all through primary school and never learned how to study. When they had to study eventually, they had a very low frustration level.

They finished school with not very good grades, struggled a lot in university, didn’t graduate and finished an apprenticeship eventually.

Even though they are pretty “gifted” (lacking for a better word), it took them decades to live up to their potential. Today they feel like they wasted their potential for way too long and find it very difficult to get the role they really want.

They still have a good job and make good money but they feel like they missed out way too much.

Of course it’s not all due to staying in kindergarten for an additional year but a series of decisions their parents made and their parents mindset.

BUT this person is still doing way better than the people I know who went to school a year too early.