Worst AI decision(s) ever?

[PvK]

I still remember way back before Version 1.25 even, I think, playing a game where I was letting the AI handle most of my empire, and I was trying to win the game ONLY (almost) by designing superior ships for my empire. Anyway, the AI sent a huge fleet of our ships, nearly half the fleet, it seemed, in one big armada towards the front line system where battles were raging. Great... except... it decided to take a "short cut" through this damaging warp point which er, just happened to lead through a... er... black hole system... OH NOOOOooooooo! Yep, so I get to watch dozens of our ships get shredded on the warp point, only to end up getting sucked slowly into the black hole, most of them either unable to escape, or worse, able to hold their ground until they run out of supplies, meanwhile costing maintenance...

Nonetheless, I still think one of the cooler aspects of SE4 is that, despite the AI's weaknesses, a player can take over just part of an empire, and let the AI handle the rest. In this way, the player can see how much of a difference they can make if they are only controlling a limited part of an empire, such as:

1) Just one particular fleet.
2) Just one particular system at a time (i.e., the emperor has to be present to take direct command, or the player is a regional governor).
3) Only reseach choices (mad scientist).
4) Only ship design (master ship designer).
5) Only construction.
6) Only diplomacy.
7) Only the military campaign against a particular enemy empire.
8) Only tactical combat.
9) Only intelligence operations.

Or, any combination of the above.

The other thing to recommend this mode of play is that it generally cuts the time required to play down to a small fraction of the usual time, even in a large and advanced game.

PvK