Mind & EverydayMental model
Nobody ignored you. They forgot your message.
Hanlon's razor: never attribute to malice that which is adequately explained by stupidity. The unanswered email, the forgotten birthday, the colleague who left you out: almost always it's stress, forgetting or overload, not intent. Assuming malice costs you anger and the relationship, while the more innocent explanation is usually the true one too.
Useful: Before getting angry, state the dumbest harmless explanation and check that first.
Source: en.wikipedia.org