When Rex Freiberger thinks of his worst auto insurance claim mistake, he remembers the time someone rear-ended his Honda Accord. “It was a small accident,” he recalls. “The damage was minimal. At first, I thought it was just body damage, and I reported that a couple of days after the fact, which was already a long time to wait.” But then he noticed two significant problems: The wiring for the taillights had been affected by the accident, eventually knocking out both lights. The bumper had also sustained internal damage. “And, most distressingly, I was experiencing headaches, nausea and some memory problems,” says Freiberger, who edits an electronics website. Lesson learned:…