Is there a problem if I don't pay? If so, what?

You have to give more details before anyone can give you a real answer on this.

Is there a problem if I don't pay? If so, what?

Is the debt secured by a lien on property you own? The creditor could (depending on the circumstances), take that property, sell it, and apply the proceeds toward your debt.

Otherwise, the creditor could sue you in court and obtain a judgment against you. Such a judgment would enable the creditor to seize your property and, again, apply the proceeds toward your debt.

Where you live, who you owe, how much, and what for.

If it is something like a credit card, or unsecured debt, they can sue you and get a judgement. Then they can merely wait till you get a job and garnish your pay.

It affects your credit and you will have a harder time getting money in the future

Chances are that you will be sorry you "forgot" the debt. In a couple years you will be back complaining "it ain't fair" when you find out you have a judgment against you for about three times as much as you presently owe.

You can try real hard to forget the debt but the debtor will likely not forget, I wouldn't. You have been asked some great questions, please try to answer them, we need more details about the type of debt.

If it's a student loan or tax debt, you don't forget about it. The disappearing tax returns and wage garnishments will remind you, and there is no SOL to wait out.