They have something of a hive mind.
They have no individual drive or goals.
They seemingly exist on to proliferate their own kind through direct contact and then puncturing of the skin.
They move rather slowly.
To an extent injury has no real impact on them short of a rather severe injury (not quite brain-stabbing, but almost close considering their armor and resistance to phaser fire.)
The Borg are basically zombies, TNG was just way ahead of the curve on the craze.