tax on tax for your USA purchases this black friday and holiday season

One thing that bothers me more then anything else is having to pay Canadian sales tax on the total retail price of an item plus the Washington state sales tax when I shop in USA

here is a sample to explain this.

I travel to Wal-Mart in Bellingham, Washington and purchase $500.00 of goods. total price is $500 + 8.7% WA sales tax = $543.50

The when I drive back to Canada and declare my goods at the border, Canada Customs sends me inside to pay 12% HST on my purchases.

But this 12% is not calculated on the $500, it is calculated on the $543.50

the total HST payable is $65.22

I know it is only a $5.22 savings that I am complaining about here but it is the point of it that pisses me off

does anyone else think that this tax on tax is unfair?