I suffer from major depression. When I go off my mess I feel like crap. I stop being able to concentrate and I feel overwhelming hopelessness. On the wrong medication I was failing basic courses at uni. On the right medication I got credit/distinctions on average and have not only held down a job for 3 years but excelled at it.
I have gone off my medication in the past because I wasn't convinced that the problem was chemical rather than environmental. When I go off my medication I'm sometimes fine for months. But eventually things get worse. I've been on the same medication for 4 years now, I've yet to have any issues.
I explored several options before settling on medication. Even then I explored the possibility that the depression was environmental or situational. I've been proven wrong each time.
Are some people incorrectly medicated? Definitely. But the idea no-one needs this medication to live a fulfilling life is reckless and ill informed.