Not entirely. I couldn't properly describe it as I've never truly experienced it - even wikipedia would do better than I would - but from those that I know who suffer from it, it's an uncontrollable sadness you just can't escape from, no matter what. You can't "fix" it. You can't just "be happy". You can't blunt-force your way to feeling better. As an analogy, it's like a cloud over you that blocks out your sun, just out of reach, and no matter what the cloud stays there, darkening your life. It's not just "sadness", and often it's married to feelings of insignificance, worthlessness, despair, and hopelessness.
The thing is... it's not really in your control. And so many people misunderstand depression and assume you can just wake up one day with a positive attitude and it'll all be okay. Or that if you overcome depression you can easily do so again. It's a legitimate health disorder and it needs proper treatment, proper help.
And that's why it's important if you know someone with depression or signs of depression that you take steps to help them. Too many people I know put on a happy face for the sake of the world, but that doesn't help get to the root of the problem. They need professional help, and we need to do what we can for friends and family to support them through this.
