Attacking units such as the Wookie's favorite targets are turrets. Often times, they will go out of their way just to attack the turrets first. Going out of their way could sometimes mean walking around an entire base and dying before reaching their target.
Forget example, here's a base setup that take advantage of a choke, funneling Wookies right into all the turrets. http://swcommander.com/viewtopic.php?f=32&t=17
Common sense would have the Wookies shoot the turrets on one side at a time, but instead, the Wookies will walk straight through the opening instead of shooting down the side wall, and as a result, step straight into the center of all the turrets. Most will die before doing any damage.