Religion
Although they are not as religious as the media sometimes portrays them to be, Spaniards are and have always been a majority Catholic nation (73% officially, although only 10% and 20% respectively admit to practicing their religion). Please respect this and refrain from saying anything that might be offensive.
Spanish people place a high value on religious holidays, especially Christmas and Holy Week (Easter). Tolerance for all religions should be practiced, particularly in large urban areas like Madrid, Barcelona, Valencia, Seville, or Malaga (where people and temples of all beliefs can be found) or various regions in southern Spain, which may have a sizable Muslim population (which makes up nearly 4% of the population of the country).