The first time I heard the idea that we are in a simulation, or that we are "a" simulation, I thought of games, in particular RPG games.

In single-player RPG games, you have "the player" and NPCs - nonplayer characters. Notice - "single-player" - as I cannot deduct if my fellow human beings are "real" or just a figment of my imagination - I think of myself as the only real player, and others are just NPCs.

While thinking so, interesting observations surfaced. You notice that the majority of the time, you are also an NPC. You are running around pre-programmed - you have routines and habits.
Also, thinking that way helps a lot to kinda "zoom-out" and see your life from the above. You notice - "oh yeah, I'm doing this, why I'm doing it the other way? In RPG it's so simple - you want to get a resource? - you got mining or trading, and of course, lot's of grinding for the unique item.".

I do not doubt that psychologically, there is an explanation or method to archive this kind of thinking without linking your self to an RPG game. But I like this game-metaphoric way of putting things into perspective.