Never, never, not in a million years, listen to a single word of advice uttered by someone who isn't happy with their life. They have absolutely nothing to teach you. This is strong stuff, granted, but I think it is tremendously important. Every single piece of bad advice I have ever received was from someone who didn't like their life. If you're unhappy, you have two basic options. You can do something to make yours…
I completely and profoundly disagree. Why do you think many great philosophers, intellectuals, and achievers have struggled with depression? Because they made bad decisions? There are plenty of idiots dispensing awful advice while wearing a smile on their face, as well. If you want to feel good, talk to a happy person that will tell you what you want to hear. If you want the truth, talk to a thinker.
You will gain something by listening to anyone. "It is the mark of an educated mind to be able to entertain a thought without accepting it." And even though THAT advice is thousands of years old, we are nothing to each other if we cannot learn vicariously from shared experience.