When you think of sadness and grief you think that they are quite similar. Sadness is when, well you feel sad about something. Sad has a lot of meanings, when you are sad you can be full of sorrow, regret, guilt, insecurities, or anxious. Sadness and grief are two different things, but they overlap. When you are grieving you can be full of sorrow, regret, and honestly anger. So they have a few things in common. But sadness and grief are not the same thing, they have many similarities and differences. The difference is that grief can include anger, but sadness can include being insecure, or anxiety, or even guilt. That is why they are two different things.