Depressing things make you feel sad or inadequate, possibly because they serve as reminders of weaknesses or defects. For example, it can be depressing to be around a happy family when all your relatives are fighting with each other.
If a friend acts as if something is depressing him, you might ask, "What's bringing you down?" In fact depress comes from the Latin word depremere, meaning "to press down." Depressing things make you feel like your spirits are low or your heart is heavy. Something depressing weighs you down, just as something happy tends to boost you or make you feel like you are flying high.