What good comes of mispronounced words?

I hear people pronouncing either as "eye-ther" and it takes some effort for me not to assume they are putting on airs. People who don't think of "nucular" as being anything but the standard way of pronouncing the word probably don't spend a lot of time on the web nattering on about it* but they may well feel that those who do pronounce it correctly are a little bit stuffy.


*What does this say about the relative levels of intelligence?