Similar example from Germany: In one year I had some "extra income" besides my job and had to file a return and pay some extra money. The next year they asked

Similar example from Germany: In one year I had some "extra income" besides my job and had to file a return and pay some extra money. The next year they asked me what my "extra income" was for that year and when the letter got lost by me they just assumed the same amount as the prior year and sent me the bill for that. After the initial shock and beating myself up for that mistake, I could simply file a correction and got it fixed with no problem.