The tax forms in my country are filled with this second-guessing. For example if it asks how much income you earned from interest, you're supposed to exclude in

The tax forms in my country are filled with this second-guessing. For example if it asks how much income you earned from interest, you're supposed to exclude income that you've already paid tax on and exclude some kinds of investment that are asked about separately in another question but they don't explain this so you have to keep tweaking the numbers until the automatic calculation looks right. There's also a question about having "returned to the country" which really confused me when I was travelling back and forth. I had to talk to the helpdesk to discover that "returned" isn't the same as "arrived after having previously left". I might have got some of the wording wrong but that's the gist.