When one's worth can be set in numbers

It's a sad thing, when some people think they are too perfect or too full of themselves to make the effort to simply greet or respond to someone who's simply giving a friendly greeting, what is it that gives such level of arrogance to think they are worthy of being on such a high pedestal? is it based on how much someone has in terms of income or reputation now? i wonder at times what makes human nature fall so far, that the worth of man can be set in numbers. Am i the only one who feels this way? or am i being too selfish myself?