One good: Farmer's Insurance sent me a letter saying they'd reviewed their records for the past 5 years and determined they'd overcharged me. There was a check for $76.82 to cover the overcharge and 10%/year simple interest.
One bad: AT&T Wireless sent me a bill for calls I'd made on the phone I'd had disconnected. The service was disconnected on 11 July, and these calls were made on 9 July. Should have been included, right? Wrong! Or, at least, so they claim. It seems they don't include delayed billing minutes from other carriers in the month in which the calls were made, but rather in the month in which they were billed - so those calls supposedly were not included in the minutes I'd paid for ending 11 July. They went ahead and credited me for those minutes, supposedly as a one-time thing. Lesson: Don't use your phone within a week of the cancellation date of the account.