As a US person, I have lived in Finland for 3 years, and I can assure you that the Finns are the most content people you can imagine! They can go months without talking to anyone and still consider themselves "happy", but the correct word in English is "content".
That report is correct, it just they advertise with the wrong word in the headline, I guess because it is more click-bate title than having it as "The most content country"
It's extremely important if you're interested in social stability. Unhappy people have a tendency to turn authoritarian and lash about, hurting both their own society and anyone who looks different.
Are they though? Alcoholism and Seasonal Affective Disorder are rife in Nordic countries.
As Finn I would agree. Finland is fine. Not the greatest and not happiest. But overall it is fine still. In most areas cost of living is pretty reasonable, services are sufficient. Police for example does good enough job. Probably could earn more money somewhere else, but why bother...