John is self-employed and did not file a return for his 2005 tax year. Eventually, the IRS prepares a substitute for return and alleges that John owes now only income tax for that year, but the penalties for failure to timely file (IRC 6651(a)(1)), failure to timely pay income taxes (IRC 6651(a)(2)), and failure to timely pay estimated taxes (IRC 6654). The IRC permits all of these penalties to be assessed at the same time, and then lets the IRS charge interest on not only the unpaid tax but all the penalties as well. Does that seem fair to you?