Continuity mistake: When Sir Ulrich is showing the rest of the group how they dance in his homeland, the camera pans back and forth to him and Jocelyn a few times and everytime it pans back to her, the people behind her are either different people or they are in different positions. (00:57:10)
Continuity mistake: When Sir William gets off his horse after defeating Count Adhemar, the hole and blood on his right shoulder disappear and then reappear. (02:06:40)
Continuity mistake: When Geoffrey jumps up to give his introduction during the final joust, he runs to the stands and you can see Jocelyn and Sir William's father just sitting next to each other. The camera angle changes and you now see Jocelyn's arm wrapped around John Thatcher's. (02:02:05)
Continuity mistake: When Heath Ledger is chatting to the little girl who tells him that his father is still alive, it is pouring down with rain and Heath brushes his hair back. It then keeps moving around. Sometimes it is brushed back and others it is hanging forwards or all tousled. (01:38:25)
Answer: The reason he is so agitated has to do with the manner in which he won the tournament. If you'll recall, William states, "I'll not be champion until I beat Adamar." Adamar had forefeited beforehand, (not wanting to joust against royalty) therefore not giving William a true victory. After his half won victory, Jocelyn's (Shannon Sossamon's character) inane chatter just rubbed him the wrong way. It had nothing to do with what she was saying...if anyone had spoken to him he would have reacted in the same way.