If you've never truly been around people with a mental illness, you would not be blamed for thinking that a lot of it is exaggerated. They can be very charming and extremely functional 99% of the time, but that 1% is the architect of their destruction and the reason why they cannot function in society. It will almost certainly rear its head if you invite them into your home / do business with them. And once they become comfortable with showing that 1% to you, oh the party begins and the regret follows.