Purpose of life is to be useful not happy

He says we do a lot of things in the pursuit of happiness that make us sad. Why?  He doesn't know,
science or something, combination of literally everything.

Why is the science unimportant?  Biologist, psychologists already have good answers for why
we do certain things.  We are programmed to want to feel good.  Dopamine, Serotonin, Endorphonins etc.
Our bodies are designed to want to maximize this feeling.  This is an evolutionary trait to give us a heuristic
for actions.  Sex feels good, food tastes good, dominance/power etc.
When you give something the ability to directly control that, they will literally nonstop activate it until
they starve to death.
http://web.stanford.edu/group/neurostudents/cgi-bin/wordpress/?p=3733

“Happiness is the meaning and the purpose of life, the whole aim and end of human existence.”
The quote of Aristotle he included in the article seems to agree with the biology, but somehow the author DF
immediately confuses the point.
DF says 'Happiness can’t be a goal in itself. Therefore, it’s not something that’s achievable.'
Ignoring the nonsense logic, we can look at his comparison with the Emerson quote.
“The purpose of life is not to be happy. It is to be useful, to be honorable, to be compassionate, to have
it make some difference that you have lived and lived well.”
Ughh.
A cursory google search tells me that this is a misquote, Emerson never said this.  It seems to me in fact, that
this is close to the opposite of what he might actually say on the matter!  The quote is an empty platitude,
prescribing how one should live their life using sweeping, broad-side-of-a-barn generalizations.  Emerson suggests
the literal reverse.  The point of life is to figure out the meaning yourself.  You are your own judge and jury.
Life is experiment, have at it.

taken from Emerson's ship mail and journal
http://www.perfectidius.com/Volume_3_1833-1835.pdf

'A man contains all that is needful to his government within himself. He is made a law unto himself:
All real good or evil that can befal [sic.] him must be from himself. He only can do himself any good or
any harm. Nothing can be given to him or taken from him but always there,, is a compensation. There is a correspondence
between the human soul and everything that exists in the world ; more properly, everything that is
known to man. Instead of studying things without the principles of them, all may be penetrated unto
within him. Eye [sic. each? every?] act puts the agent in a new condition. The purpose of life seems to be to acquaint
a man with himself. He is not to live to the future as described to him, but to live to the real future
by living to the real present. The highest revelation is that God is in every man.'

scattered thoughts:

what is useful anyways, useful to who? society?  A lot of his examples are entrepreneurship based.  A useful
business is by no means a specifically kind, caring, or compassionate one.  Useful to others at the detriment
of myself? Seems like that would generate unhappiness for me.  Useful only when it's mutually beneficial?
He avoids specificity in the same way as a horoscope.

other emerson quotes

Why he would not tell others how they should live their lives
'I wish to write such rhymes as shall not suggest a restraint, but contrariwise the wildest freedom.'

He didn't want to live for the sake of society
'Man exists for his own sake and not to add a laborer to the state'

My issue is that this person could have done the same as me and googled/read for an hour or two, but didn't.
Why? Because they don't need to.  They are maximizing their time spent vs clicks received, they're selling ebooks
and self help and can't spend too much time on a single ad.
https://www.amazon.com/THINK-STRAIGHT-Change-Your-Thoughts/dp/1721225749/ref=cm_cr_arp_d_product_top?ie=UTF8
More power to him, it's hard to make money and be successful.

But that doesn't mean we need to take him seriously.