How do I show the feelings of a sad person through a 1st person point of view?

Question:

How do I show the feelings of a sad person through a 1st person point of view?

The subject is in Language Arts...and we have to list 5 ideas.

Best Answer - Chosen by Asker:

The simple answer is that it is tricky because being the view point character, too much "I am SO sad" becomes tedious.
Other people can notice behavior.
Being put in situations where cheerfulness is called for and not showing enough.
Writing a letter and crying on it or not being able to finish it because it has to be uplifting (condolences on a death for example) and author can't be happy.
Seeing happy people and turning away to avoid having to join them.
Being abrupt on the phone and having the caller react to it.