In people with good mental health, this natural state allows them to get on with their lives, experiencing everyday triumphs and failures and maintaining a fairly positive outlook. Depending on the type and extent of the depression, the level may range from mild unhappiness to uncontrollable misery. Good and bad events can still raise and lower the level to a certain extent, but the underlying feeling is constantly negative, and bad events have far more influence than good. Even though there's apparently nothing wrong with their social life and career, depressed people can feel as though their life is not worth living and they are totally alone. It is a frightening, confusing and deeply unhappy experience, which is why depression can be hard to escape from without help.
Perception is the key.
To someone in good mental health, the sky may seem blue, birds are singing, people are pleasantly chatty. It's all a matter of interpretation and perception, which is controlled by brain chemistry, but which can also be influenced by the person concerned. To borrow a phrase, 'The optimist believes we live in the best of all possible worlds. So it is with depression. And because depression is all about relative emotions, it can affect anyone, from a homeless person to the richest, most powerful people in the world.