There are two verbs that mean "to be" in Spanish: ser and estar. As described to me, one is essential and the other is contingent. That is, ser is for describing things that you always are: soy ingles, soy un hombre, and so on, whereas estar describes transient states of being: estoy cansado, estoy encima de la mesa, estoy loco por los bocanadas del cocoa. If that is the case, it poses problematic philosophical questions about the mutability of identity, gender and citizenship.
For a start, it might be quite nice to be able to say "yo soy cansado" without being accused of grammatical wrongdoing. Consider if you will an Iberian Liam Gallagher, lead singer from Oasis (that’s the Spanish for "Oasis" in case you didn’t know). His continual state of enthusiasm seems too strong to be just "yo estoy loco por ella"; Liam should be mad for it all the time, the quintessence of his existence.
Similarly, if we accept that gender is a social construct and not just a matter of being in one of two, immutable categories, it would make more sense to say "estoy Una mujer" than my Spanish teacher might currently give credit for. Alternately, think of the trouble they may have had when they dubbed Orlando into Spanish, complete with gender hopping and Tilda Swinton staring terrifyingly.
Finally, what of nationality? If ser really picks out the permanent aspects of existence, then we struggle with things like being British, or changing from one country to another.
Perhaps the Spaniards never had to worry about dual nationalities. That would explain something, although in not sure what.
It’s possible that I’ve massively misinterpreted everything about ser and estar. Until this morning, I think I had a 95% chance of not using por or Para correctly, so this wouldn’t come as any surprise. I shall ask my teacher this weekend and see if she chases me down the hallway with a broom for attempting crimes against language.