Many years ago, it was against the law to drive with your lights on in this popular vacation country. And this incorrect bit of information still occasionally pops up on lists providing tips for vacation travel. But the Spanish still are not accustomed to daytime running light. The same thing still occasionally happens to me in Spain that was so common in Germany 20 years ago: Spanish drivers flash their lights at me, “reminding” me to turn off my lights.
The Spanish have an unusual custom when it comes to securing the site of a breakdown or accident: in Spain the warning triangle is placed in front of the vehicle, not behind.