When you need to borrow money (through a loan, a mortgage, etc.) you should look for the lowest interest rates.
An interest rate is the amount charged for the loan, which is calculated as a proportion of its total amount or principal. It is the profit of the lender.
If, on the other hand, you act as a lender by depositing your savings in a bank or on any investment fund, you would seek the highest interest rates offered as in this case the interest is your retribution.