Personal income tax returns must be filed on time. If the return is filed on time, there is no late filing penalty, even if there is a balance owing. Personal income taxes must also be paid on time. If the balance is paid late, then interest is charged. File late and you get a penalty, pay late and you owe interest. You avoid late filing penalties by filing on time and you avoid interest by paying on time.
CRA has a couple of types of interest. Installment interest if you did not pay your tax installments when asked and arrears interest if you did not pay the balance owing on time. The strategy is to file on time even if you cannot afford to make the payment. If you do that, you will owe CRA less money because there will not be a penalty added to what you already owe. So the punch line here is, file your personal tax return, even if you do not have the money to pay the bill.