When your taxes are not paid the IRS establishes a lien against all of your assets (especially real estate). This gives the IRS the legal right to collect the unpaid taxes from the sale of your assets, which includes just about everything you own.
The lien can be against you, your spouse, or your company. A lien against your company would seize your accounts receivables. .
Liens filed against you by the IRS also show up on your credit report and often prevent you from opening a checking account or borrowing against any assets, like your home. You would not be able to acquire low interest rate car loans or be able to buy or sell real estate. The list is endless.