A Mexican, who speaks no English, comes to the USA. As is often the case, he finds that he needs new socks. So, he walks into a clothing store, and manages to convey to the clerk that he needs something, but not what.
So, the clerk starts taking down boxes and showing what's inside to the Mexican. He shows him a shirt, some pants, a tie, a hat, but each time the Mexican shakes his head and says "No."

Finally, the clerk brings down a box of socks and shows them to the Mexican. The Mexican starts nodding vigorously and says "¡Eso sí que es!"

The clerk angrily blurts out, "Well why didn't you just spell it in the first place?!"