I will say there's a strong difference between best and favourite for me. My favourite is Fable 2 which isn't the most boastful in terms of RPG mechanics but honestly, it's a comfort.
In my opinion, It's Fallout New Vegas.
The expansive world, the crazy questlines, it was one of the first games I experienced where my playthrough was not the same as the other people I knew who were playing it. (aka my dad lol)
Although as I'm playing through Baldur's Gate 3 right now, that answer may change.
