EB forests annoy me to death. They are so dense that the AIs troops get stuck and it screws up their path finding. I've had enemy forces march across the battlefield and out the other side and leave because one of the men got caught on a tree. Happens quite a bit but it's not too bad as long as I don't try to move the unit too far away from those who got stuck. Another big annoyance is when a soldier gets stuck before he enters battle and you've basically lost control of that unit.