Europeans won’t mind if you support your soccer team loudly, except perhaps when their team is playing yours. Tou won’t be as loud as they are used to. In the Euro 1996 championship in England I was a Scotland vs England game where the jingoism was threatening, but that can happen even between club teams. I’d have no problem with Germans singing Deutschland Uber Alles, especially since it is played before the game as their national anthem.
Dutch polite can be rude and brusque, but it’s not aimed at you, it is just they don’t consider these things as important. I never once saw a Dutch man hold a door open for a woman or offer to help her with a load, and they are contemptuous of foriegners who do as they see it as superficial and old-fashioned. Although the Dutch women seemed to lap up a bit of chivalry.
French people have a heirarchy of rudeness. Ordinary French people will mostly be lovely to tourists. Ordinary Parisians are contemptuous of other French people. The rudest French people are Parisians whose job it is to help tourists, especially the clerk at railway stations that have a British or American flag next to them. Tourists assume that is to indicate English is spoken, but in reality it is where English speakers queue to be berated for the amusement of the French people queuing. If you speak fluent French in any foriegn accent they are merely contemptuous and sarcastic, but their full ‘Fawlty Towers’ strop starts on your first minor grammatical error.
Rude, insufferable, obnoxious american tourists do exist, and I have first hand anectdotes that are cringeworthy, but like Teacake said just your default volume can be disconcerting. I have equally as many tales of Britons abroad, and certainly I stop talking English abroad whenever I hear a British or an American accent.
