I want to be clear--I believe the immigrants should assimilate, they should learn English, take part in our national holidays, adopt our patriotic traditions. If they don't, they will continue to work at Subway and clean hotel rooms. That said, if they want to communicate in their native language amongst themselves that is their prerogative, but I would hope they would use that time to practice their English.
In JediKnight's example, the woman was probably looking for a Spanish speaking salesperson to make communication more efficient. Her attitude was the problem.
In CarPro's example of the Mexican dude that wanted to remain a Mexican but live in the US, I think that person is wrong.