It's not a stupid thing to ask at all!
I think some people simply enjoy reminiscing. I know when I meet up with old friends it's fun to have a bit of conversation about "oh, remember when we did xyz". However it's totally OK for you to not get any enjoyment out of that and you're right that it could be unhelpful to hold onto the past and fixate on wanting things to be like that. As long as it's just a bit of nostalgia and enjoy old memories I don't think that's unhealthy.
Does that make any sense?