I just figured out a better example:
You can spend Saturday walking through forest, or walking by the lake, or gardening at home. Let's say that objectively, all of the three activities are identical in terms of value added to your life.
You choose the lake.
Next day an alien/angel figure appears and asks you to judge and justify to him how well you spent the time, on a scale 1 to 10. Your judgment, feeling, and answer is going to vary based on where you exactly are when being asked:
- If you happen to be by the same lake again, you will give 10. Your brain will be much better at producing the justification by reminding you what you have seen and thought about.
- If you happen to be by the forest, then you will give 5. It will be harder to come with justification, your memories won't be accessed so readily. However you're still "on a walk", so there's some overlap
- If you happen to be at home gardening, you will give 3. You are now in a completely different mindset and you have probably realized few more things to do in the garden.
Of course, your judgment will vary based on other factors as well, such as your mood, or your relation to the figure.
So my point is that no matter any objective measure (if such thing even exists), your judgments of the time spent will vary by many factors, and the difference in context will certainly contribute to the difference in judgment.