Another reason to be careful on facebook?

good point

untrue, someone can have severe depression yet still try to enjoy life, go through the motions etc, whether it makes a difference or not is debatable. Depending on the severity of depression it may impact their ability to work, ability to work with others, ability to deal with work deadlines, stress etc. People can be depressed enough to damage careers, family life, yet could have days where they are doing well.

lastly, there is something called bipolar disorder, aka manic-despressive concept, where a person can ping pong between mania and depression.