Jo had learnt to try to wait until whatever exhausting emotion is done having feelings.
Anger more often than grief, but that tended to be a consequence of her lack of sleep.
Even so, she couldn't help but wonder if she really were to let herself get angry, she'd never stop being angry.
Sometimes it's all she thinks about.
(Because the memories, dreams and nightmares that would inevitably come in her sleep also had their own terrible toll.)