If you're ever involved in a criminal trial with the IRS, your accountant may be forced to testify against you. Just imagine the sinking feeling you would have in a criminal trial if you heard an IRS lawyer say "Your honor, we would like to call the defendant's accountant to the stand".
Penalties and interest add up by the day if you haven't paid the IRS what you owe them. And they add up big-time if you haven't filed at all. Every day that you put off taking care of your IRS problem only makes it worse. Did You File and Not Pay? If you did, there's interest being compounded daily on what you owe, which is the quarterly federal short-term tax rate, plus 3%. As of this writing, the IRS is charging 4% per year.
The Internal Revenue Service recently released information that government employees on Capitol Hill owe overdue taxes worth $9.3 million, as part of the per agency IRS debt breakdown. It is not clear whether there are some Congress members guilty of not properly paying their taxes, as the agency refused to specify those involved.