When thinking about the most important moment(s) of your life, do you still feel the full range of emotion associated with that memory? What if you keep recalling the same memory many times, does the intensity of emotion fade?
I think this question would fit better on askscience.
The short answer is that the emotions themselves don't "fade", but every time you recall a memory, you are also recalling all previous recalls, and the emotions related to the event you remember are not the same as the emotions on each subsequent recall.
We use computers as an analogy for the 🧠, and there are some reasons for that, but they are not the same, and this analogy have limits.
The brain evolved to keep us alive, and reproduce. Keep a perfect record of previous events would be costly and unnecessary for that. "Learn the lesson" and keep a registry that resembles the past is enough.
(But I'm not a neuroscientist, so I may be wrong, missing something or not updated)