It can be a mistake to go back and perhaps destroy happy memories.
This, this, and this.
I actively avoid trying to re-live the past, because it isn't possible, and attempts to do it spoil the memories. When you build memories you gild the lily, remembering the good bits and forgetting the rest, so even if it were possible to recreate the past exactly it's bound to be a disappointment because it never was actually that good. Re-runs of old TV programs are the proof of that, they
really are just as they were, but you quickly realise just how little of them contributed to the memories you treasure, with the rest just being dross. For example, TOTP2: good, because it's all cherry-picked golden oldies, TOTP: you're lucky if there's one good song per episode.
In practice, an event is more than just itself, your experience of it depends on
all sorts that can't be repeated, from the company you were with, to the weather, to how the rest of your life was going at the time.
The
Peak-End Effect demonstrates what's going on. It's tempting to think that your memory of an experience is just the average of the whole episode, but research has shown that this is not the case: your memory of an event, good or bad, is the average of the best (or worst) bit, and the last bit. The
peak and the
end. This leads to the counterintuitive result that you can make the subjective memory of a bad experience less bad by making the actual experience objectively worse: just add on an extra bit at the end which is less bad than the ending you're appending it to. You can also make a good experience create a better memory: ever heard the phrase
leaving the best till last?