a friend of mine tells people he is from canada when he travels...doesn't want people to know he is american
I would say that's the most cowardly and repulsive thing I have ever heard. Why pretend? Just tell your friend to move to Canada, America doesn't need people like that.
Americans have plenty to be proud of, as long as we can be humble about it. There are a lot of American a**holes but that's even more reason to be a better person and set a better example to the world when you travel to other countries. Don't pretend you're a Canadian or Australian, just be a better American than any foreigner would expect and win back respect with your actions and your attitude (be humble).
It is not cowardly and repulsive. If you had spent years living, traveling, working out of the US, you would know this is an entirely wise thing to do. You apparently have not, nevertheless you feel free to opinionate on it.
Living inside your bubble you do not understand that to the rest of the world, the American overreach since 9/11 has become very real, and unavoidable. Several mideast wars for dubious reasons, FACTA growing like an octopus across the world financial system, the NSA back dooring into the private lives of non US citizens through hardware, Skype, Facebook, deep ocean internet cable monitoring and anything else the they can think of - this is the day to day experience of the US for people who are not Americans. It is not a matter of a 'some americans being a-holes'. It is a matter of a complacent and once-free citizenry being apathetic to a hollowing out of their own constitution, and a lethargic acceptance of their government trampling on the natural human rights, privacy and independence of others across the world.
I recommend the book "Dirty Wars" by Jeremy Shahill. In which American tax dollars end with an intentional drone strike on a 16 year old boy. This is the America many are seeing from the outside and you are not.