I had a fairly spectacular embaressment as the Italians. I went to war with the Byzantines and decided to invade one of their islands which was defended only by only one unit of spearmen. I took a my heir to the throne prince and his royal knights and two units of genoese sailors. I was employing my usual tactic for this kind of battle which is parade my knights up and down while their spears trot along after them, meanwhile my archers are wasting them then my knights would chase the routers to a man so I wouldnt have to storm the keep. (I've always found this works very well)
Well heres what happened.....
It was going great, they were down to maybe 30% of their initial size and I hadnt lost a man. My grilfriend walks in the room and wanting to show off at the cool features of MTW I said "come and look at this" and switched the 'follow projectiles' option on and gloated as my arrows thudded into the enemy. What I hadnt noticed is how close the spears had got to my prince.... the coward, obviously worried about the threat to his rear ran like a girl before a single blow was even struck! I rallied his unit twice but he immediately fled again each time (nowhere near the enemy!). My sailors easily handled the spears, but 1 or 2 of the enemy escaped. After the battle my prince got two negative morale vices and the port was destroyed. In disgust I sent no reinforcements and left him there to die in the uprising which occured the next turn and NO I didnt ransom him back - I felt my empire was better of without him!

I have never seen a unit, especially knights, do that before. He wasnt that tired, had no morale vices (at that point) and hadnt even lost a man, but he runs from a depleted spear unit without a fight??? So much for chivalry!