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 yourself happier, or you can rationalise a reason why happiness isn't possible. The former is generally a steady upward slog. The latter is like quicksand - the longer you're there, the more solidly you become stuck.
All the bad career advice I got was from people who didn't like their job. Some believed that jobs were just inherently unpleasant, so you might as well go for the unpleasantness that pays the most and gives the best pension. Some believed that good jobs were just inaccessible for 'the likes of us', so there's no point getting you hopes up. Some were so uncertain of their employability that they took the first job offered to them and never dared do anything to jeopardise it. I heard rationalisations dressed up as philosophy, as ethics, as macroeconomics, but they were rationalisations all the same.
Learning from the mistakes of others is useful and productive, but an unhappy person can never provide any insight into how to be happy. Either they don't know what would make them happy, or worse, they do know but won't do it. Never underestimate how hard someone will work to rationalise why they just can't go back to college or start their own business or visit Europe or leave their awful wife.
When seeking advice, ignore status, intelligence and experience. Seek out the happy people, they're the only people who can help you.