Friendship energy

I got a friend request from someone I used to know. But I didn’t accept. They aren’t a bad person and there was no falling out or animosity. I just don’t want to go there. The best way to explain it is there is no friendship energy anymore. This person and I used to get along really well and we hung out a lot. It seemed we had many things in common. But when they took a different job and I didn’t see them as much, something shifted. And I couldn’t figure out if their personality changed, or if they had characteristics I hadn’t seen before. Whatever it was, things between us weren’t the same and we drifted apart. There was no goodbye, no unanswered messages, no discussion. The friendship faded away. And then I got their friend request. I don’t know if they want to be friends in real life or just have me on their page to know what I am up to. Either way I wish no ill will, but I have no interest in being friends again.