Three words...Rock Me Amadeus
I was a German language student at that time. Was conflicted by Nena—attracted by the look and the language but hadn’t yet embraced European armpits... 99 was simpleminded but complex compared to another of my faves: “Da Da Da” by Trio was also very catchy and popular at the time. Simple repetitive lyrics over a cheap Casio keyboard made me wonder if all German popsters were perhaps a bit slow. The Klaus Nomi memorial barrage pretty well put me off German music. Would have gone decades without purposefully listening had Rammstein not appeared in the late 90s.