Why is there so much ignorance regarding epilepsy?

It's 2007, and I have friends with epilepsy who encounter ignorance and sometimes open hostility on a daily basis. People act as though epilepsy is catching, treat them as though they are mentally ill or mentally retarded, and tell them that 'they don't look like they have epilepsy". Epilepsy is the third most common neurological disorder in the world. It's not rare. So why are many people so clueless about it?
The one that gets me is that people would tell someone that 'they don't look like they have epilepsy' WTF? How is a person with epilepsy supposed to look? It's bizarre.