"A Fact Graph is a DAG, just like Excel." [1]
A DAG won't work for everything! For example, the advance premium tax credit (i.e., the means-tested Obamacare health premium subsidy) has a circular relationship with the above-the-line deduction that self-employed people can take for healthcare costs. The IRS says you can iterate until you get stable values. [2]
Even if you're pulling in 100% of your income through a W-2 job and you're sure you're not itemizing, you have to consider excluded income, above-the-line deductions, and refundable and non-refundable credits. Oh, and do you live alone or might you claim a dependent,[1] and on and on and on. People spend their whole lives on this stuff and still don't understand the half of it.
They probably know less than you think. (Are you selling stuff at the farmer's market for cash? Did you gift your coin collection to your grandkids?) Making everyone file reduces fraud somewhat – but whether that's worth the country's time and effort is a different story.
Used to be, you could get a seedy OBD cable off Amazon and it came with instructions on how to "acquire" the dealer software, which let you reprogram the car to accept any fob. Not sure if things have changed in the last 5 years.
You set your own display name on Signal. You can also set "nicknames" for each of your contacts, but they're local to your account. If a nickname is set, it overrides the display name in most places in the UI.