Be careful how you treat people. I have heard this statement many times in my life, and I am sure you have too. When a person experiences success, it is human nature to think he did it by himself. Unknowingly, arrogance creeps in. He forgets the very people who helped him along the way. He stops answering phone calls and responding to emails from the very people who were there for him on his journey.
What he does not realize is that life runs in cycles. One minute (week, month, year, or decade) you are up but the next minute you are down. This is called life and it happens to everyone. However, only the self-aware realize it. The very person you ignore today most certainly will be the very person you will need tomorrow.