No matter how much money you have, someone else has more.
No matter how beautiful or handsome you are, there is someone in the world who looks better than you.
No matter how big of a house you live in, another person probably has a much bigger house than you.
No matter how intelligent you are, there is a damn good chance there is someone smarter than you out there.
No matter how expensive and fast your car is, I'm fairly certain someone else has a more expensive and faster car than you.
Confidence in yourself is great, but remain humble. It will serve you well in life.