There is a huge amount of interesting thought experiments, for example, if we are simulated then it's possible to save the state of the simulation, stop it, re-apply a previous state etc. We could all vanish in the next second because the universe got reset to a previous state.
Who is to say this hasn't happened tons of times already? You wouldn't know because you got restored to a previous state with no knowledge of that one time that something went horribly wrong and the universe reloaded to a previous state.
