On my trip to Spain last week, we saw some unexpected things:

In Sevilla, at Mass at La Magdalena, we saw several (Spanish) men wearing shorts at Mass and even women with sleeveless dresses. The temperatures in Andalucia were in the 100's and Shorts were very common wear.

When we got back to Madrid, our host had on 'cargo' shorts. We wore shorts to dinner at El Pato Mudo, at the Tryp Diana in Barajas.
I told Carlos that if they said anything I would show my US Passport and claim Tourist dispensation.

In reply to my question, our host's very fashionable daughter (PhD Speech Therapist) said that white socks were now acceptable with 'Mocasines' or 'Plataformas.' It's the Michael Jackson look: tight fitting slacks to just above the ankles and white or grey (or gold - like Michael Jackson) socks.