I still like them. On the World Capitals A-Z quiz, these four capitals are each guessed about 45% of the time, which might be a bit too difficult. Anyways, not every quiz has to be hard.
Not sure if you're joking or not, but just in case: you're thinking of Zurich the largest city in Switzerland, whose capital is indeed Bern. Zagreb, meanwhile, is both the capital of and largest city in Croatia.
Reading the title of the quiz, I thought, it's gonna be a pretty tough one. But when I saw that initial letters and continents were given, it took me 12 seconds...
What a surprise when I plucked up the courage and found that there were only 4! With the continents listed! In quiz order! Wonderful!