[just a few of brief thoughts that I mind expand upon later;]

Greek is not necessarily difficult

Greek might seem exotic and very difficult, but other than the new alphabet and possibly the declension system — which is much more prevalent than in English or Portuguese (for the unaware: it comprises the rules for the use of he/him, or how the possessive changes for "o meu carro / a minha casa") — other than that, I feel like there is not much to account for in terms of language difficulty (granted, I haven't been exposed to the more experimental sentence structures to be found in colloquial everyday use: «δεν μπορώ ρε ψυχί μου φέτος. Έχει και το παιδί φροντιστήρια», an example found in a comic book that completely overturns expectations of a sane, logical line of thought: the latter could be translated to something like "exists, for the kid, extracurricular activities", just to convey "and there's the kid's extracurricular activities).

there is a big overlap in concepts

As I get more and more comfortable with Greek, I notice how many ideas seem to be conveyed in a similar way, using very close metaphors, or plainly referring to the same concepts. An example would be how the three languages make use of the concept of having ("há muitos dias que / έχω μέρες για ... / it's been days since") to convey the passage of time; or to say of oneself to be found in some place ("encontro-me aqui / βρίσκομαι εδώ / I find myself here"). There are probably better examples — I'll find them in my own time, ή με την ησύχια μου... — but point stands that I was expecting more radical differences. I wonder what factors come into play to explain such similarities (the overarching influence of Greek? The role of Latin? I have no idea, and linguistics probably studies the matter).

a lot of vocabulary is shared (and I sort of took it for granted)

In the last year, I had a handful of mobility opportunities that put me in touch with many groups of international people. Of course, English is the middle ground in which most of communication stands, and I would consider myself a proficient practicioner of the language — so many books, internet, stand-up comedy, it was bound to help somehow.

Some recent interactions have left me wary of language accessibility, though: coming from Portuguese, it is natural to transfer words like efémero (ephemeral), exótico (exotic) — there's many more! —, while, from what I understand, these connections are not so evident coming from, for example, (some) slavic languages. So I am keen in exploring the implications of famililiar languages (granted, my exposure to this matter is limited and thus it might be a moot point from its very start; it could just be that the particular demographic that triggered this idea is not particularly invested in expanding vocabulary).