Comment: I'm a Canadian who has travelled to Europe 12 times in the last 5 years. The only time I've heard disparaging comments about America is in Russia . And even then it's not overt but implied. I can tell you however, strictly based on anecdotal evidence that Canadians are well recieved anywhere I've travelled throughout Europe, especially Russia. 
There's an old saying, the people ate good but the leaders are evil. And without a doubt George W. Bush was loathed throughout Europe during his term. I didn't get a sense however that Obama was loved either. 
Let's face it, regardless of where you travel around the world, your citizenship only matters if you put yourself in a situation that compromises your safety. I've never seen an American act crassly or obnoxiously or entitled because that's not smart. However I've seen Canadians around an airline check in counter in Germany make want to go to the back of the line for a time out.