The IRS views failing to pay payroll taxes as the cardinal sin of tax delinquency. Not paying your company's payroll taxes is tantamount to stealing your employees' money in the eyes of the IRS.
As a result, penalties for failing to timely pay your payroll taxes or file your payroll tax returns are much more severe than other penalties. They can drastically multiply the amount you owe in a very short time.
If you are behind on paying payroll taxes for your company, know that the IRS is extremely aggressive pursuing collection of this type of tax. DO NOT meet with the IRS on your own. How you answer their initial questions can determine how agressively the IRS pursues collection. It is critical you hire a professional representative who knows how the IRS operates.