Why am I not humble always??

I don't know anything.I know some people who are always down to earth or humble in-spite of their huge success..,they are just beautiful people... are they born like this?

But I tend to go out of humbleness(or not being down to earth) after every little,little achievements.. Because of this I suffer,face pains in this life. Because of this, I can not work on my dreams consistently. Because of this, I can't go up on my dreams of achievement. Because of this I always come 'back to square one' after trying to work on my dreams number of times. I always want to be humble..