Grief takes on many different forms for different people and in different circumstances. These are just the few ways grief shows itself.
For anyone who recently lost someone they were not close to, the grief associated with such a loss may be more apathetic than anything else. You or the person who recently experienced the loss may seem quiet, somewhat withdrawn and not seem particularly upset at all. They may seem like things are fine but it may simply be that they are processing the grief more internally. Just because they are not grieving outwardly does not mean they do not feel the pain of loss in their own way.
At times, grief manifests itself as anger. The bereaved may feel angry that their loved one has left them. They may feel anger towards those trying to help them; they may feel the efforts of their friends and family are not enough. They may even feel angry at themselves for failing their lost loved one even if there was nothing they could have done. When grief shows itself as anger, being patient is key. Just know that they likely don't mean the harsh things that may come out of their mouth.
Sometimes, after a loved one has battled a long illness or has lived a full life, grief is tempered by a feeling of relief or even peace at the end of a loved one's suffering. Some religions even encourage comfort in the loss of a loved one. These faiths preach that death is not the end and a lost loved one is perpetually cared for without suffering in a better place. For some, the loss of a loved one is not a sad one, but a matter of comfort and joy at the end of physical suffering.
Grief does not always present itself as the sadness and crying that many think characterizes what loss looks like. There are some that don't shed a single tear during the bereavement process. Everyone grieves differently and knowing some of the ways grief shows itself can help you or those you love better work through their loss.