Lived temporarily in Seoul and Osaka last year for three months, then moved to Berlin.
The trains were always on time in Seoul and Osaka when I had to take them (though to be fair, not very often) but in the first week of being in Berlin, like 60% of the time the "trains are running at an irregular interval". I definitely don't trust the U/S-Bahn in Berlin, but it's still one of my most favourite public transport systems in a city I've lived in. Lived there for 2 years and never had to use a car.
The trains were always on time in Seoul and Osaka when I had to take them (though to be fair, not very often) but in the first week of being in Berlin, like 60% of the time the "trains are running at an irregular interval". I definitely don't trust the U/S-Bahn in Berlin, but it's still one of my most favourite public transport systems in a city I've lived in. Lived there for 2 years and never had to use a car.