When you realize you’re in “good days” the feeling is called bittersweet. Therefore one should make the most, as soon as you realize the time is bittersweet. This helps prevent regrets of “not doing enough” later. Like today, it’s not too late to make the most of your upcoming weekend.
Its not possible; good old days always exist as a retrospective of the past, you never experience the present with all the bad parts removed
What if you experience the present without any bad parts?
Brain damage?
This is why stoicism has the concept of prospective retrospection.