You so Crazy...Do we take Mental Health seriously enough?

Everybody's got a friend or family member that may be a little off.  You love this person and they are normally pretty functional, but they are also known to be unpredictable, volatile and maybe even abusive. For whatever reason they disconnect with reality and everyone knows it.  Yet nobody does a thing. When do you dismiss a personality quirk and recognize them crazy?  Tell us what you think and if you know anybody that could be diagnosed, but has no clue they are cray...