This is a tough topic with the potential for heated diametrically-opposed opinions.
I too have had the experience of living a big chunk of my life outside the US, about 18 years, between South America (mostly Argentina) and Europe. I've also split my time in the US between east and west coast.
When abroad I have at times felt embarrassed to call myself an American. Well, first of all, I hate the use of the term "American" because, well, we don't own the entire continent. I feels utterly ignorant to say "I am an American". In the UK at least you can say that you are a "Yank" and it is more accurate. Anyhow, this might be a minor point. Just because it is convenient I'll continue to use the ignorant reference and call myself an "American" in this post.
Yes, Americans are fat and ignorant. At least that's a big part of what we project. Some of it has to do with how egocentric we tend to be. I have met Americans that have a hard time placing countries --much less cities-- on the globe. You often hear things like "I can't spell" or "I am not good at math". I can't recall ever hearing such expressions in other countries. If you can't spell your own language or handle high-school level math you are actually looked down upon in a lot of cultures. Just one step above an idiot. It really sounds moronic from the vantage point of other cultures. So, be aware of this fact. While it might seem funny to you to make a comment like that, the other person could be thinking that you are a "burro".
I am the last person to propose that government get involved in directing behavior through taxation and the like. I've posted before on the whole healthcare law mess. However, there is one tax credit that I could probably get behind in a serious way if it was implemented correctly: A tax incentive to have Americans travel abroad with some frequency.
I truly believe that we would fix a LOT of problems both here and elsewhere if the average US citizen had a more accurate world view. In Europe it is easy to travel from culture to culture. It's just a train ride away and it can be really cheap. Here in the US it is harder and far more costly. It is logical that most would simply travel a few hundred miles away within our country than get on a plane and see other shores. An intelligently-done tax credit to promote foreign travel could do wonders in this area. We need people to travel out of the country a few times (not just once) during their lifetime to gain perspective and learn.
If the average American understood what the world looks like on the outside and, perhaps more importantly, what the US looks like when looking-in, they would behave differently and vote differently. We would be a different country.
The topic of religion in the US is also a tough one. I, like most, grew up in a religious environment and later rejected it. As an atheist now I can't help but see some of what goes on with all religions as nothing less than lunacy. A collectively accepted state of dementia. A tsunami kills hundreds of thousands of people and the religious still can't logically look at the gaping holes in their demented belief system. At one point you'd hope that someone would rationalize that if their god truly listened to their prayers and helped their football team win a game while allowing someone to get killed or raped across town, or someone else half beaten to death at the stadium parking lot or hundreds of thousands of of people die in an earthquake...well, something ain't right.
Anyhow, the fact that American politics is so overly loaded with the need to express devotion, dedication and history with one religion, Christianity, is of great concern to those of us who can look at things from a different plane of thought.
From outside our country this looks ignorant and, well, ridiculous.
There are so many consequences to having religion as a dominant force in politics. Gay rights and scientific research are two examples that come to mind. It is personally offensive to me --not gay-- to hear believers who consider the gay to be unholy abominations (and worst). When you try to explain that being gay is a genetic mutation (not a pejorative) that is no different from having blue eyes they laugh at you. That's when the topic of evolution often comes-up. It is personally offensive to me that they challenge evolution as though anything they could offer is even remotely relevant to the conversation. You try to explain that the mechanism for evolution is the very reason that their kids don't look like perfect clones of each other, and they come up with counter-reasons that one couldn't even imagine. And, when religion mixes with politics you have things like the drive to teach "creationism" to our kids. Again, from many distant shores this looks nothing less than retarded. And they are right.
A lot of the above is very negative. Here's the good news: There is a TON that is great about this country and this people. We, with all of our faults, manage to have created a society that is orderly and, for the most part, law-driven. Just ask an Argentinian about how their crazy governments and rampant corruption at all levels has, effectively, destroyed what used to be a very nice country. In the US we disagree. And, yes, polarization is horrible right now, but we somehow manage to run things reasonably well.
There's also a lot of creativity in this land. There are cultures that have huge issues with this. Both Europe and Asia have examples of this effect. A lot of the behaviors and culture that the US promotes internally lead to finding diamonds in the rough and allowing them to shine through.
Yes, here you can be nobody and rise to be anything and anyone you can dream of becoming. And that's why the US has led the world in a technical and, yes, cultural revolution that has had no equal. I am proud of being an American, warts and all. I strive to be above average and make sure that my kids develop a world view and cross cultural view from the get go. I also respect other cultures and understand that nearly everyone who is positive in the world has something valuable to offer. I could go on, but that's probably enough of a brain dump on this topic.