Born i Stockholm, I remember taking the ferry to Finland as a young boy for some cheap vodka (and you only had to be 18 years old, not 20).
This was in the late 70's and my first visit to Helsinki, I tried to order a drink in a bar. But no service until I discovered my mistake: I had spoken in Swedish.
Switching to English got me a nice Finnish beer. That was my first glimpse of Finland's "complicated" history.