Usually there are specific whims that point you in the right direction as to how to reduce the duration of the angry moodlet. For example 'take an angry poop'. Yep, you read that right! Also sometimes taking a bath or shower or 'venting'/complaining about problems. You'll know if what you are doing is reducing the duration of the angry moodlet as if you hover your mouse over it there will be little arrows moving downwards and the timer (of how long the angry moodlet will last) will be counting down. Failing that, just keep the child happier, or some other emotion that is stronger than the angry one, until it wears off.
