Why in Spanish do they say “Buenos días” instead of “Buen día”?

<p><em>This is a translation of the&nbsp;</em><a href="https://medium.com/@peter.palta?p=25d88604b563" rel="noopener"><em>original article</em></a><em>&nbsp;in Spanish.</em></p> <p>I got palta&hellip;</p> <p>Why do we greet with &ldquo;good morning (buenos d&iacute;as)&rdquo; when we can say &ldquo;good day (buen d&iacute;a)&rdquo;?</p> <p>It is obvious that when we greet we are referring to the present. With this greeting I express my wish that the other person have a good day today. In fact, this is how other languages ​understand it, so they consequently use the singular form. However, the Spanish language is the only one that greets in plural.</p> <p><a href="https://medium.com/@peter.palta/why-in-spanish-do-they-say-buenos-d%C3%ADas-instead-of-buen-d%C3%ADa-575a2b668bc9"><strong>Website</strong></a></p>