When you are raised poor or in perpetual economic peril, no matter how much money you may ever have in your life, you're always expecting to have your credit card denied, to have your check bounce, to have your power shut off, to be evicted, to be discriminated against, to be judged, to be arrested. My husband -- a Jewish doctor's son who was raised solidly in the Upper Middle Class -- finds it an absolutely mindboggling, inexplicable habit, but to this day, I still religiously save all of my store receipts -- not just because I might need to return something...but to have as an alibi should I ever be wrongly accused of a crime. That class insecurity never goes away. Ever.