Dollar coins are treated not as the currency that they are, but rather as novelty items. They're a treat for children, not a coin for every day use. At least, that is what the American public seems to think on the matter.
One paper dollar bill costs the government 4.2 cents to make and has a life span of about 20 months. One dollar coin costs the government almost three times as much to make at 12 cents per coin, but the life span of a dollar coin is 30 years. In other words, for the government to keep one paper dollar bill in circulation for the same length of time as a dollar coin, it would cost the government about 76 cents. Considering the number of dollar bills that are in circulation, Americans could save their government (and thereby themselves in taxes) quite a bit of money every year simply by using dollar coins instead of paper bills.
The vending machines that sell stamps in most post offices give dollar coins as change (though they don't accept them in payment, oddly enough). You can also get dollar coins simply by going to the bank and asking for them. (Granted, you'll have to exchange some paper money for them. Rob, my husband, usually buys $80 worth of dollar coins at a time.)
Simply by using dollar coins, you can expose others to them. The more people become comfortable with dollar coins, the more they may be willing to use them.
Come on, you reticent Americans. The Canadians have not only dollar coins, but two dollar coins as well! If they can do it then we bloody well can too.