Why do people ignore other people? It is not as if you are too small to see...in fact you are too big and tall you can paint the whole sky. WikiAnswers gives us this 'answer'...
If you think about why people ignore one another, it basically comes down to this, the person being ignored is not worthy of your attention. Clearly, this creates a bit of a "better than thou" issue, and the person being ignored is usually unhappy that people think themselves better than him. An enlightened thing to do would be to discover why they're being ignored. However, because people are A. unenlightened and B. assured that questioning the person ignoring them is futile, they prefer to go on the offensive against the person who thinks themselves their better. In a sense, it's a matter of attracting attention, so that the problem may be resolved. Do keep in mind though that ignoring people is not only rude, but also ignorant to a degree. We only ignore people we consider useless to us. After all, no one ignores someone they consider helpful to their cause.
A li'l philosophy may help those having doubts on their existence. This one is from huge-entity.com...
If I didn't exist, then I wouldn't be able to attempt to prove anything, or even to think I existed in the first place.
Photo credits: deviantART
