My perspective is this:
The US has been in a tailspin with the Bush administration. While not everything is Bush's fault, I feel however, that he has not handled it well as a leader should.
We are in a war that is resembling Vietnam, we are in an economic crisis with neither side willing to come to terms with the other.
Our healthcare system is in need of a major overhaul, but at what expense? The same goes for our educational system.
No, our country is not perfect, and we have lots of room for improvement.
But there are things here that we take for granted.
Here, we can marry whom we chose to, whereas in places such as India where you must marry within your own caste.
We have freedom of the press, whereas in places such as China and North Korea, the press is government run. They tell you only what they want you to know.
We have the freedom to make our own destiny, but it is up to ourselves whether or not we succeed in those endeavors. In other countries, your destiny is chosen for you such as in remote Africa or Brazil, where are born, raised, live, and die all within a 20 square mile area. Whatever your father did for a living, is likely what you will do for a living. In certain places, the cities and slums are so violent you are a dead man walking just to step outside your door to go get groceries or to hang your laundry to dry.
Look at Mexico, there is a valid reason why they are coming here. They literally live in paper houses and they are ill-educated where many children begin working street jobs by the age od 10-12 to supplement their parents meager income.
Talk to an immigrant from Mexico, you will be surprised that many of them did not know what a washing machine was when they got here. Microwaves are science fiction in the poorest slums, and many have the educational equivalent of the 5th or 6th grade, in their native language, they are barely able to function in English, but some learn and some dont. But here, learning English is free, whereas in Mexico, learning English is simply unaffordable for many. If you know English in Mexico you are gauranteed a job at any tourist destination as a guide, front desk worker, or travel agent. Otherwise you are limited to farm or factory work, or scrubbing toilets for less than $2 a day.
Here we have boundless opportunities, in other countries, opportunities are hard to come by.
Lastly but not least, we are one of the few countries where it is legal to complain about all the things that are wrong and/or unjust about our country. In North Korea, this is grounds for treason and your family is split, your sent to a camp where you are worked, starved, and beat to death.