"In Spain, people eat paella."?

Hola Clare,

This "se" is a passive form, i.e. it is another way to say "something is done" (ser + participle). The verb is conjugated agreeing with whatever is eaten, done, caught, drank, etc. So in this sentence:

"Se come paella."

Who eats paella (people) is not mentioned. 

The verb comer is conjugated in the 3rd person singular to agree with "paella". 

The confusion might come when the translation in English is "People eat paella", as you can see a different structure in the English "People (subject) eat (verb) paella (object)". There is no literal way in English to match with the Spanish "Se come paella"; sometimes "People eat paella" or "Paella is eaten" or ""One eats paella". We try to use the most natural translation for this type of sentence.

I hope this clarified it.

Un saludo 

Inma