I was going to say replaying but I feel like that limits the question to games like Prey or Fallout New Vegas that have endings and games like The Sims 2 or Cities Skylines where you can play indefinitely end up excluded.
I’m not really referring to games like League of Legends where you’re coming back every month. More so games where you stop playing for an extended period of time.
Neverwinter Nights (the first one) and Heroes of Might and Magic (3 and 4). They’re just so comfortable for me to play so I just start them up when I’m to stressed out to play anything new.
Every few years I replay Gothic 1 or 2. Are these great games? Yes. Is it also because of nostalgia? Yeah
Also from time to time I reinstall black flag… Mostly for the feeling of sailing