“To be successful you need friends and to be very successful you need enemies.”

Misattributed

Quotations by 60 Greatest Indians, Dhirubhai Ambani Institute of Information and Communication Technology http://resourcecentre.daiict.ac.in/eresources/iresources/quotations.html,

Mark Twain's Notebook, 1887
Letter to Cordelia Welsh Foote (Cincinnati), 2 December 1887. Letter reprinted http://www.twainquotes.com/Success.html in Benjamin De Casseres's When Huck Finn Went Highbrow https://www.worldcat.org/title/when-huck-finn-went-highbrow/oclc/2514292 (1934)

Succeeding in Science: Some Rules of Thumb (1993)
Context: To have success in science, you need some luck.
But to succeed in science, you need a lot more than luck. And it's not enough to be smart — lots of people are very bright and get nowhere in life. In my view, you have to combine intelligence with a willingness not to follow conventions when they block your path forward.

Source: Feet of Clay

Out of Control: The New Biology of Machines, Social Systems and the Economic World (1995), New Rules for the New Economy: 10 Radical Strategies for a Connected World (1999)

Don Soderquist “ The Wal-Mart Way: The Inside Story of the Success of the World's Largest Company https://books.google.com/books?id=mIxwVLXdyjQC&lpg=PR9&dq=Don%20Soderquist&pg=PR9#v=onepage&q=Don%20Soderquist&f=false, Thomas Nelson, April 2005, p. 115.
On working hard

as quoted by [Steven Chu and Charles H. Townes, Biographical Memoirs V.83, National Academies Press, 2003, http://www.nap.edu/catalog.php?record_id=10830, 0-309-08699-X, 201]

Source: Economic Warfare Quotes