Ecclesiastes 2:10

2:10 I did not restrain myself from getting whatever I wanted;

I did not deny myself anything that would bring me pleasure.

So all my accomplishments gave me joy;

this was my reward for all my effort.

Ecclesiastes 2:21

2:21 For a man may do his work with wisdom, knowledge, and skill;

however, he must hand over the fruit of his labor as an inheritance

to someone else who did not work for it.

This also is futile, and an awful injustice!