Just imagine if you were playing chess against an opponent and as soon as you made your carefully planned movement the other player immediately made his move and it was your turn again right away. It feels pretty aggressive, doesn't it?
So I gave players the impression of the computer taking time to think by instituting a random delay (within a given range which I tested until it felt right) before it acted, and I think it felt a lot more natural and less aggressive because of that.
If people are curious about the game, it's easy to find and you can play it online.
I even turned down a request from the Puzzle Pirates guys to include it as a minigame in their game (that was a mistake), and OmgPop almost paid me to make a version for their website (shortly before they made Draw Something and got bought by Zynga), but I was too busy trying to finish my degree at the time.
I've been tempted to start an open source version to get some help developing it, but I started getting more into board game design lately and I've been programming less and less in my spare time. Kinda hoping I get a reputation in the board game world and then get a board game version of Proximity published (it's an abstract, so it's a harder sell to publishers).
Anyway, I'm glad you enjoyed the game. Hopefully someday I'll put out a newer version of it.
I've also done this in some programs I wrote as a teenager to solve math / physics homework to make it seem like it was doing more than it was.
DigitalOcean's Create Droplet flow comes to mind. You get a progress bar indicating your droplet is being created, but in just a few seconds you can click "My Droplets" and go use it immediately.
On HN there was this about Well Fargo "Establishing Secure Connection".
It was pretty hilarious.
I got a bug-fix from the form developer that his button wasn't working, and I kept trying to explain to him that it couldn't possibly work, it didn't do anything.
Finally he explained that if the user had clicked the fake button already, and then changed their search to a search that reported the same results, it wasn't pretending to search again, and this was causing a lot of bug reports from his client.
I helped him rewrite the fake button to make a bigger deal about (fake) searching again, and apparently the bug reports went away.