This is very true, paranoia begets paranoia. If someone senses your paranoia it tends to escalate. They might start to get paranoid because they sense that something is not right. Each party then takes a more defensive stance with each email until someone backs out of the sale.
"Paranoia strikes deep
Into your life it will creep
It starts when you're always afraid
You step out of line, the man come and take you away"
-- Buffalo Springfield

