When someone consistently talks about someone from the past even in a negative light

I've always wondered, when someone constantly brings someone else from the past up in a conversation, whether it is in a positive or negative light, does it mean they actually still may either miss them or still feel affected by them whether it was good or bad? Even if they deny missing someone or that someone who may have had a negative influence on them no longer has an effect on them, I wonder if them constantly bringing up the person means they secretly do miss them or something else is going on.

If it is in a positive light, then they may be longing for the old times to be back. If it is in a negative light, then I wonder if it is because they still feel hurt by that person even if they deny it and even say they actually don't care. Another reason I wonder is because they may have had several people in their past that they dislike, but they are rarely brought up. Except for one person. Makes me wonder if it is due to lingering feelings of resentment or in some cases, wishing that things could be good between them again if they used to be friends.

I have a friend that does this. We used to be friends with someone else that turned out to be toxic and to this day, my friend talks about her as if this person had just slighted her even though they haven't talked in years. They used to be good friends. It is one of those cases where I wonder if she wishes they could still be friends, which is understandable. I feel the same way about some people. I wish some people had been nicer and better friends as well. But the point is, I am willing to admit it. I wish some friendships of the past had not gone sour. But some people, including my friend, will state that they do not miss the person at all even though they constantly bring them up. Makes it seem like they secretly miss someone but don’t want to admit it.

What do you guys think? Have you known anyone who has done that or may have even done it yourself? I know it may be hard to admit to missing someone even if they turned into a toxic friend. It’s normal to wish things had been better if things went sour. Do you know anyone from the past that you still miss in a way and wish things had been better or that they had been a better friend? Just wondered.