Is it networking or is it sucking up?

How about networking? Is it sucking up or connecting? Who hurts or helps a career the most? Others or your own? Who were your mentors and supporters once you got out there? Was it someone who looked like you or other? People say we are our own worst enemy so I'm curious. Often our biggest supporters look nothing like us. We also get in our own way in personal relationships, when is advice or support destructive instead of constructive? Do we have to kiss ass in order to be successful in business? Is it wrong to do so? Would we sell someone out to get ahead? What is selling out?