The detailed explanation is as follows:

1. First of all, the 80-day tax arrears in loans overdue have exceeded the threshold of severity, indicating that the debtor's long-term failure to repay the loan belongs to the category of serious breach of contract.

2. Secondly, overdue tax loans for 80 days may lead to serious consequences. When the debtor is overdue for a long time, the tax authorities or banks may take a series of measures, such as freezing the debtor's bank account, sealing up and auctioning his property, and even taking legal measures to recover the debt.

3. In addition, a tax loan overdue for 80 days will have a serious impact on the debtor's credit record. Credit record is an important basis for evaluating personal credit status. Overdue repayment will lead to a decline in credit rating, which may further make debtors encounter difficulties in future loans, credit cards and other credit aspects.

4. To sum up, it is a serious situation that the tax loan is overdue for 80 days, which may lead to serious consequences and have a serious impact on personal credit records.

Extended data:

1. Overdue repayment refers to the debtor's failure to repay the loan or pay interest on time after the agreed repayment date, which is generally divided into different degrees according to the length of overdue time. The longer the overdue period, the greater the impact.

2. Tax loans refer to loans that individuals or enterprises apply to banks or other financial institutions to meet the actual business or personal consumption needs of taxpayers. Usually, tax loans are closely related to taxpayers' tax records and credit records, and overdue repayment will directly affect taxpayers' credit status and financial stability.

3. For debtors, the best way to avoid the consequences of tax loans overdue is to plan and manage their financial situation in advance to ensure timely repayment. If it is really impossible to repay the loan on time, communicate with the bank or relevant institutions in time to find a reasonable solution to avoid further deterioration.

The above is the answer and explanation of the seriousness of the 80-day tax in loans overdue, which is more than 300 words and provides additional extended information. I hope I can help you.