There is a big difference between a liar, a bullshiter and a delusional person.
A bullshitter seems to be what your describing, and I wouldn't even call it lieing, it's called being an entertaining character, as only the stupidest of people fall for it.
What's far more difficult to discern is a person thats lies versus a person that is delusional. The line is typically paper thin, and it really takes good detective work to discover the difference.
Our whole society is dependent on delusions and lies.
It's pretty much a sign one in mentally alright, one that lacks delusions or is too honest will likely suffer from clinical depression, or some anti social behavior issue.
When you have aspergers, lies and delusions become measure of a persons character.