What are the causes of an IRS tax problem?

Generally there are there a couple of ways in which an IRS tax problem occurs, but generally the single most common way you can a have tax problem is that there is a balance due with the IRS. 

If you don’t owe the IRS any money then they’re not going to bother you. The IRS doesn’t perceive that there is a problem. 
There are two common ways in which there can be a balance due to the IRS. 

First, you may have filed a tax return, and there was a balance that you never paid. Of course interest and penalties continue to accrue while you don’t pay. 

Another way in which you can have a balance with the IRS is that if you never filed a tax return in the first place. If you wait long enough the IRS will do what is called an SFR, or substitute for return or service filed return. 

In this case, the IRS will take the information that they have about your income and prepare tax returns for you.   In many instances, this will result in a higher tax liability than if you had filed the tax return yourself.

Obviously, this is probably not the best thing that could happen to you.