My first computer (1993) was a desktop 486DX with proprietary local bus that ran Windows 3.1. I bought it used off an EE who built it from parts. He had used it for Autocad, which he used for architectural design purposes. He had decided to get a laptop instead. I found it in the classified section of my local newspaper, took the train to his house and talked to him for must have been 2 hours before I bought it, I was a newbie, brought it home on the train.
I found a free computer chess game that I installed on the machine and lost every time I played. I'd regarded that computer as my salvation, my chance to develop the chops to make me eminently employable. However, losing to that machine every time in chess (probably around a dozen games) was giving me the creeps and I started regarding the machine as my adversary. Dark feelings were developing and I stopped playing chess with it, the bad feelings quickly went away. I have never played computer chess since. Was the machine sentient? Of course not, but I had projected negative emotions on it, I couldn't help doing so and had to stop playing chess with it.
I remember coding a battleship game in C++ class in college. The requirements were low and I met them within like an hour of class but we had a whole week to do it, so every class I just kept adding on to it. I would not go as far as saying I coded an AI because it was not really AI at all, but I did code it in such a way that I can have the computer handle game play the same way as a human. Ex: it could not just cheat by looking at the data of where the player placed the ships, it was looking at the board the same way as a player and could do the same kind of moves etc. I then added a lot of smart logic to the strategy of how the "AI" played. Basically fairly normal battleship logic and lot of randomization, except I had it dialed in so well that the computer beat me almost every time. People thought I just made the code cheat, like it would just look where you placed your ship, but not at all. I also had PC speaker sound effects but I ended up turning those off since it was starting to annoy people in class lol.
I think I still have that on a floppy somewhere actually, I need to see if I can recompile it to run in Linux.