Out of curiosity, are you happy with your life? :)
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.
But there are very few philosophers I would want to take advice from. I'd like a debate with Nietzsche, Schopenhaeur, Kant, ... and many others.
But would I take their advice about how to live my life in a pragmatic way? Hell, no.
Secondly, advice is about what you should do, not what is true. A subtle, but important, distinction.
Some people are bitter by design. No matter what I do, I will always have many complains to be unhappy about. Right now, I am trying to boot-up my startup. If it doesn't work, I will be bitter. If it works out, I will be bitter about my other pet peeve - schools killing creativity and I would like to contribute towards making it better. If it too is sorted out, I would be bitter about people being bitter about each other owing to religious, regional or some other non-rational biases. I am bitter about Government corruption and lack of infrastructure in my country. I am bitter about common man's rights not implemented in spirit. I am bitter about morons dividing people on religion and reason, and worse, people listening to them.
All of these isn't going to change(some might) in my lifetime. And the only way to be happy about it is to turn a blind eye. If happiness is ignorance, I don't seek it.
This would be blatant generalization, but many happy people I have met are blissfully ignorant. They have accepted life as is, and are happy with the current state of thing.
I generally listen to all advice, and ignore most of it - the adviser being happy or not doesn't figure in my criteria.
Of course, things should be placed in context. An advice of a bitter math teacher on mathematics will always be better than an advice from a happy ignorant person.
On a personal note, don't be bitter. You can accomplish the same without the bitterness, it's just weighing you down.
He assumes there is no reason to be unhappy, completely ignoring the various reasons I have pointed out and stated that ignoring them would lead to bliss, but that's not what I seek.
What about what-not-to-do advice?
You can go further than rationalization of one's choices to a desire to validate them by preventing success by others.
This chimes with my personal experience. I suppose the demographic I'm from in the UK gave me certain blind spots and self imposed ceilings. I'm now 25 and only just starting to figure out and balance against them.
I grew up in a small fishing village in the North of Scotland - where everyone (and I mean everyone) was very supportive of education and the idea that anyone pretty much do anything they wanted if they had ability and worked hard enough. My parents weren't well off but all 4 of my siblings and I went to university.
My wife comes from a urban-working class background in a post-industrial area near Glasgow, she is extremely bright and went to University at 16. However, she had to constantly battle a "that's not for the likes of us" attitude from everyone in her community, including her parents (who are nice people, but just don't "get it").
When we first met she always made fun of me for having no concept of "class" whereas it was something that had always been made clear to her by her peers. Ironically, she became a lawyer and entered that bastion of upper middle class eccentric respectablilty: the Scottish Bar.
>>When seeking advice, ignore status, intelligence and experience. Seek out the happy people, they're the only people who can help you.
That argument needs that I would become happy following the same path as the person giving advice. That is just not true for quite a few happy people I know.
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.