I'm upset by the volume and the lack of diversity in immigration, legal or illegal. Too many people from one country or one culture makes it too difficult for them to assimilate and if they're from a 3rd world country their economic impact will be negative. It doesn't matter if they come through legal or illegal channels.
So all of those Colombian and Venezuelans bankers (I know more than a few), Indian doctors, Korean businessmen and Pakistani physicist will be more of a drain than the Russians who I would always see using their food stamp card at the supermarkets in Brooklyn?
Actually, legal immigration is handled via a national origin lottery, so it shifts from year to year. Its ILLEGAL immigration that makes total immigration waves disproportionately from Mexico.