There is parable in my language about a person that worked hard, relentlessly - not giving himself any time to rest and enjoy life - and apparently it worked! he managed to horde a huge pile of gold! the man became older, and one day - the neighbors found him dead - laying alone on top of his mountain of gold.

the referent in the original story is different - but let's take it to our topic - you can work alone on things, sure, you might even meet success if you work hard without any rest, and you might become really rich and "successful" after along time of hard work. but does it worth it?

So yeah - cooperation will probably make you be more successful, if you do it the right way - but a great benefit of sharing is that you work with PEOPLE, people to whom you get close, you enjoy being with them and working with them!
that way - not only you'll probably be more successful in achieving your goals, but you will have some free time, friends, and you'll enjoy the work itself! when you do something that is important for you, with people you like - work becomes fun by itself.

come and join us at ADSactly, you'll find good,cooperating people to hang with and to work with, achieving new goals and enjoying it.