In some countries, rather than sending you a bill, the government calculates what you owe and then refuses to tell you. You are then responsible for working out the same solution they did and then paying them (note that both steps are hard, and the government may refuse payment without explanation).

If you successfully pay them and the payment was too low, they may come after you, typically with fines, but if you fucked up badly enough, potentially even jail time. Same thing if you did not succeed in paying them at all, because that will count as failure to file even though it's their fault.

If you overpay, the government chuckles and pockets the difference.

It's really just a meme anyway. I'm American and do my own taxes. It's labyrinthine, but not actually that hard honestly.

The place where individuals get themselves in trouble with the government is the more subtle business related stuff like writing off expenses, carrying forward business losses, depreciating assets, selling stock. That stuff is probably best left to an accountant.

But as a regular person filing with mortgage deduction, college tuition deduction, child tax credits, if you make a mistake the most likely response is just gonna be a letter telling you to try again.