All of the countries of the world have a July 4th, but in the United States that particular date has a particular significance, it is the date upon which we celebrate our independence, the "Birthday of our Country".
When someone wishes me a "Happy 4th", I kinda wish they'd call the holiday by its real name "Independence Day". It's not a big deal, and I know what they meant, but I try to wish them a "Happy Independence Day" in return.
Kim DuToit at The Other Side of Kim has a good essay on the meaning of Independence Day on his blog, and it's worth having a look. In his essay he quotes Ronald Reagan, and I have reproduced that quotation below.
“Somewhere in our growing up we began to be aware of the meaning of days and with that awareness came the birth of patriotism. July Fourth is the birthday of our nation. I believed as a boy, and believe even more today, that it is the birthday of the greatest nation on earth… In recent years, however, I’ve come to think of that day as more than just the birthday of a nation. It also commemorates the only true philosophical revolution in all history. Oh, there have been revolutions before and since ours. But those revolutions simply exchanged one set of rules for another. Ours was a revolution that changed the very concept of government. Let the Fourth of July always be a reminder that here in this land, for the first time, it was decided that man is born with certain God-given rights; that government is only a convenience created and managed by the people, with no powers of its own except those voluntarily granted to it by the people. We sometimes forget that great truth, and we never should. Happy Fourth of July.”- Ronald Reagan
Happy Independence Day, from Mr. C., KeeWee, Rocket, the goldfish, and all the bunnies......