One of my favourite blogs is "Adventures of a Gringa" written by New-Yorker Rachel. Link to her blog on the right side of this page or here. She has lived for a couple of years in Brazil and makes Other Top Ten lists you can read clicking here.
Top Ten Ways to Piss Off a Brazilian
10. Mention the World Cup of 1950, 1998, or 2006.
9. Ask him what the rainforest is like when a Brazilian tells you he's from Sao Paulo or Rio.
8. Say, "I hear Buenos Aires is really nice. That's your capital, right?"
7. Make sexual innuendo and imply she is a slut when you find out a woman is Brazilian.
6. Forget to take a shower and/or put on deodorant before coming in close contact with a Brazilian.
5. Talk with your mouth full, and chew with your mouth open.
4. Declare your love for Argentina, Argentines, Boca Juniors, or Maradona.
3. Speak Spanish with him, since that is what language you assume he speaks.
2. Fail to answer anything but a very enthusiastic YES when asked if you like Brazil.
1. Criticize Brazil or Brazilians by making any remotely negative comment about either subject.