Manners and "politeness" in Spain

[Alik]

I have never been to Spain nor any other Spanish speaking countries. Yet ,from my teacher and other sources, I have always had the impression that the Spanish people are more easily offended than South Americans, is this true?

For example, is it true that the Spanish don't like people who are too "polite" (i.e. A person who says please and thank you a lot)?

Is it true that South Americans are more extroverted and 'warm'? How do the Spanish treat foreigners?

I am of course talking generally as I know not everyone is the same. This is something that I've always found curious. What do you guys think?

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Yo nunca he estado en España o en un otro pais hispanohablante. Sin enmbargo, yo siempre tuve la impresión de que los espanoles son más fácilmente ofendidos que los súdamericanos, ¿es esto verdad?

Por ejemplo, ¿es verdad que a los españoles no les gustan personas que son demasiadamente 'cortés' (Una persona que dice mucho por favores y gracias)

¿Es verdad que los sudamericanos son más extrovertidos y cariñosos? ¿Como es que los españoles tratan a los extranjeros?

Yo estoy hablando generalmente. Yo sé que todos no son iguales. ¿Qué piensan?

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PS: And this reminds me of another thing. Regarding "Ustedes/Vosotros", I know ustedes is formal but in most situations I don't see the need for formalities. Is someone considered rude if he doesn't address a stranger as usted?