There sure are a lot of different days when Americans celebrate thing or another. And being a prime example of a capitalistic nation they have commercialized every one of those. There is always a special sales going around during those days.
For us non-americans in these days of global economy it's a great thing. As those vendors selling in the internet don't care where the buyer actually lives. So we get all the benefit for those sales even if we don't celebrate the same things.
In addition to that, we have our own national special days. And following the example of the U.S we do tend to have all kinds of great deals during those days. In the matter of fact, we have it even better than the Americans, as we can benefit from both of them. We have twice the opportunities to buy things for cheap. Not to say that it's a good thing from environmental point of view. But doing it sustainable and also economically at the same time isn't that bad. If you really need to buy something why not buy it when you can get it the cheapest. And at the rate of those special days pop up in the calendar there isn't usually a long time to wait.