So I'm a triangle too.
Lost in between circles and squares.
When you leave your home country there is one thing that you don't think about: you'll never be the same again.
I mean, of course, everyone is evolving and this not depending on the place they are living. But when I was 21 and left France, I never thought I wouldn't be able to readapt to my own country (in fact, when I came to Spain, sorry, Barcelona, I was really thinking to stay 6 months only, so I was far away from thinking about this).
The good and bad thing at the same time is that you're a stranger in the new country (wohooo, plenty of new things to do/see, new people to get to know and millions of new [good and bad] experiences just because you're new) but little by little by sipping all this new culture, you're also becoming a stranger in your home country. You're starting to feel, as they say in Spanish "ni pa' lla, ni pa' ca".
As explained in Naomi Hattaway's post http://naomihattaway.com/2013/09/i-am-a-triangle-and-other-thoughts-on-repatriation/, just try to make fit a triangle into a rounded or squared shape...!
This strange feeling is a bit hard to explain to both your family and friends who stayed in the country and to the locals. So you smile and say "yes" when they tell you that after such a long time, you surely feel Spaniard/Catalan by now. In your family, they even call you "the Spanish girl"... But even after 10 years, I do neither feel Spaniard nor Catalan. And never will feel it... even if I had gotten the nationality. Even if I really like this country.
Do I still feel French? Well, in my case, I come from a mixed family with Polish blood in my veins. Not sure that I am the best example of a typical French product... But I still carry all the heritage from the education I received and still follow the typical behaviours such as complaining, standing up for causes I trust in and joining protests (a typical national French sport), craving for yummy pastries and good wines and cheeses, being passionate for festivals and cultural events, waiting for a man to hold me the door and be a gentleman (yes, call me retro!)... And little by little I dropped the general negativism and morose attitude we usually have in my home country. Also tried to get rid of the typical criticism and judgments made way too quickly about people you barely know. And learnt to think out of the box, too. I also ended up making friends with more foreigners than locals or with Spaniards who have spent a time abroad too, and not even consciously, but in the end, I know they will understand me perfectly.
The interesting fact about moving abroad is maybe that you get to know your home country better. Or you see it with a different perspective.
The hard thing is to get to a point you don't know where you really belong to. Still, I want to believe that the triangle can find its own place, whether in the middle of the circles or in the middle of the squares :)