You must not know anyone well who has depression then. A person can intellectually see that their life is not so bad ... but their emotional and corresponding

You must not know anyone well who has depression then. A person can intellectually see that their life is not so bad ... but their emotional and corresponding physical state are an entirely different matter. An analogy I make sometimes is this. Have you ever been scared while watching a scary movie, or laughed at a comedy or teared up at a fictional drama? Even though your intellect knows the thing you are watching is an artificial event that never really happened, your emotional state and your physical state don't care what your intellectual understanding is.