It's one thing to be able to say, "no one is better than me." It's another thing to believe it. I live with an inferiority complex to the point where merely writing the words, "no one is better than me," feels ludicrous and as if it should be followed by a chorus of, "of course they are, everyone is." For me, it goes as far as whenever someone touches me, I have to consciously dismiss the thought that they wouldn't if they knew how inferior I was.
It's not an easy self perception to live with. Especially in a world that defines authority figures as "your superiors", where every group has it's alpha, where social hierarchies exist as much as professional ones, where it often seems as though everyone defines almost every social relationship based on who is the superior one. It leads you to allow other people to get the promotion, the job, the girl. And that just reinforces your own perception of yourself.
But that's all it is - perception. Your perception of yourself. Believing you are inferior to others because of your own shortcomings or because of how you don't fit into the world. We can say how everyone has the same struggles and insecurities, but the trick is to look around and actually see it. Look how many people are awkwardly sit there not knowing what to say, watch people try to say something funny that ends up sounding atrociously dumb. I know that boisterous loud guy in the other office, he takes anti-depressants for his anxiety disorder and often drives halfway home before coming back to go over his work because he's so afraid of missing something important. That girl who was the head of the It crowd in college, she was degrading herself into letting her boyfriend perform perverse acts on her because she was afraid he'd leave her if she didn't because she believed she wasn't lovable without doing those things. Realise that when you experience an awkward silence, that they can't think of what to say either and probably feel the same as you do.
What makes it worse is that people will react to your own self perceptions. Whenever you're in a social situation, every time you contract within yourself, they will expand into a dominating position. Conversely, as you expand they too will contract. You have to learn to remember you are in control of the situation - because the truth is that they are as lost as you are.