I once did my kid’s taxes by hand.
A few weeks later I got a form letter from the state. It said I had made a mistake....and the refund should not be $34....instead it should be $34,000 (I have terrible handwriting).
The letter said we would get a check for $34k soon. It never came...and neither did the $34 check :(.
Once got a letter from the IRS stating that my return wasn’t the amount I gave them (forget the amount ). Instead it should be x, the exact same amount.