I don’t know, chess? Might have also been the only time when I was impressed…

I find it helps that chess:

• can easily be represented in digital state and tons of research has gone into chess AI.
• is turn-based, allowing our measly human brains to compute some fraction of all the scenarios that an algorithm can take into account.
• does not hide information. There’s no fog of war or field of view or such. AIs don’t get fed screenshots containing only the things that you as a player can see. They need to be implemented with alternative information, like actually just knowing the player coordinates, even if the player is behind a wall. If instead there is no hidden information, then it makes it much easier to implement the AI, by just using all available information…