Race

The concept that your race changes as you fly to another country is so strange! In America our veiws of race are so integrated into how we think it is almost incomprehesible to view it from others perspectives. For example the fact that in Brazil there are over a dozen racial categories based upon the shade of skin...although they're more individualized in there categories and it is not as clear cut as black and white it's still not acceptable. So....what is accpetable? Why would we possibley need to categorize race as we do? If there is no need to categorize, how do we stop?