It would take a lot to wear out Amaterasu's near infinite patience. Though she may seem rather stern and is definitely not afraid to scold dragons for reckless behaviour that may end up with them getting injured, her first priority is to help those that come to her no matter how many times she told them not to provoke that particular familiar. Nobody has ever seen her lose her temper.
She is not afraid to speak her mind, and can sometimes be rather brutally honest when reprimanding those who have failed to heed her advice. In fact, Amaterasu prides herself on her honesty, and will always speak the truth. If there's one thing she can't stand, it's liars.
When treating another dragon, Amaterasu will adopt a strict, motherly attitude. Anything which might endanger her patient's health even slightly is strictly forbidden, but on the flip side whoever she's looking after is guaranteed the best food, comfiest sleeping area and warmest blankets until Amaterasu is certain they are fully healed.
Piasa is a frequent visitor to Amaterasu because of her frequent, dangerous trips to the coliseum and her unwillingness to back down. Amaterasu has given up trying to discourage her from these trips, and simply sighs and gets straight to work on the many occasions Piasa comes limping into her lair. In fact, she has even offered to accompany Piasa to the coliseum on occasion in an attempt to stop her getting hurt in the first place. Piasa always accepts, although she wishes Amaterasu would attack more instead of constantly casting healing spells.
New to the clan, Amaterasu had not heard the stories about Ryuujin and found him charming and sweet. She quickly agreed to having a clutch of eggs with him, only then to find out he was not actually looking for a long term relationship. Instead of being angry or upset with him, she simply told him that he should think more about other dragon's feelings. The two remained friends.
However, after quite some time Ryuujin began to realise he cared about Amaterasu as more than a friend. After pouring out his heart to her, which he'd never had to do before in his life, they ended up having another nest together. Since then nobody is quite sure what is going on between them. Ryuujin continues to flirt with other dragons, but Amaterasu appears to be fully aware of the situation and still continues to have occasional nests with him.