If tacos — somewhat shaped like mouths — could talk, there would be an argument of such epic proportions that every Mexican restaurant would be forced to give out free earplugs. The (marinated) beef would be between the Tex-Mex version of fast-food chains and the simple, authentic, ungarnished magic offered at a place such as El Carnal. The first, drowning in a sea of sour cream and iceberg lettuce, would be screaming for help, unsure of its identity as it resembles only a shell (a hard, fried one at that) of what it was in Mexico. The second would brag about its slow-marinated carne asada; pineapple-grilled pork al pastor; and seasoned cuts of tongue served in corn tortillas with an assortment of simple sauces from which to choose ($2). It would have all the reason to be smug, self-righteous, and pretentious in its defense of all that is authentic, but — served at a hole-in-the-wall street-food joint with space for only a handful of customers — it would choose instead to be simply welcoming.