I can write couple books about depression but the ultimate truth is, even the most depressive person who fell into abyss of apathy and despair can move mountains if he wants to. Difference between deeply depressive and happy people is, despressive people don't feel emotions most of the time but they can still make strides forward and be successful. Some are very good at hiding that and push themselves too much to hide it, so you sometimes can't tell who is depressive. Take late Robin Williams for example, he was extremely successful actor who never gave away his sadness but deep down he fell into abyss so deep he killed himself in the end. You can be successful while being depressive but you'll act like a robot most of the time, regaining control over your emotions is very hard task and thus keeping relationships becomes increasingly difficult under those circumstances.
I'm mostly depressive but I fight it but not thinking about it or about big ideas, just push forward with small tasks and you'll be golden. Problems depressive people may face are hurdles on their journey through life, the more depressive you have the bigger chance you'll break apart trying to overcome certain difficulty that pops up on your path. Healthy people are dealing better with difficulties while mentally fragile aka depressive people can be pushed backwards by it. Which is why it is important to be nice to people and enable them to do great things and not be pricks like Oberyn.
We're all more or less depressive deep down but people who need medicine to deal with it are called junkies. At 13 years old first though of killing myself came to me, naturally I'm a dreamer (sign: pisces) which means that puberty left me with many questions and doubts that led me into severe depression. Suicidal thoughts never materialized but lasted through adolescence. After having near death experience I will never again thinking about suicide, because having suicide is the most stupid thing a human can do in their life no matter the circumstances. There is no afterlife thus living is the only thing we have, if you take that away from yourself you've got nothing. Even tiny portion of life under heaviest possible pain is better than nothing. There is no heaven that awaits martyrs and those who went through hardships. For similar reasons it is remarkably stupid conscripting into army and fighting for your country in wars, because you risk your life for practically nothing in return. Same people who believe in afterlife are willingly putting their life on the line for somebody else and going to war.
Major problem with issues we face in life is that society won't help you, sometimes they try but do it the wrong way, most of the time they just exploit you. Big reason for depression is shit we consume on daily basis and society is doing nothing to change that. When you're depressive you eat shit, get fat and as result become more depressive and helpless. That is an extremely vicious circle supported by extremely vicious people who were probably depressive themselves but ignored it and focused on work, attained important roles in society but in the mean time turned into sociopaths.
Edit: In case you haven't noticed I'm exceptionally mean when I'm feeling depressed. It comes out strong and doesn't last long. Few ways to went it, I prefer online and not to bother people close to me. They call that bipolar disorder but I don't have many highs and those highs are mild. As of lately I'm mean a lot less frequently because I'm mostly dealing with depression. Bipolar disorder like many mental disorders aren't very well defined because they greatly differ from individual to individual yet they prescript same quantities of brute force drugs to everybody. Mental disorders are so complex psychologists are mostly acting like medieval butchers operating on vital tissue.
You can easily see who of us gotten better over time and who got worse. Those who got significantly worse still deny their depression and mental issues. Is there an other way to explain obsessive behavior and general hostileness towards others most of the time than psychological issues? I don't deny I have issues but they do. It will bite them in the end.
