As a Dutch person, I'm actually gonna say Amsterdam. So crowded, chaotic and getting run over by other tourists on bikes they've never ridden before. I feel like it's romanticized a lot because it's our capital but the first time I visited, I was genuinely disappointed. It's definitely dirtier on the streets and the canals have a lot of waste drifting in them.
And the people that are there don't seem to understand. "Honey, you're in Amsterdam, isn't it fantastic?" "I'm living the dream because I'm living in Amsterdam!" "Amsterdam is the heart and soul of the Netherlands!"
Meh. I'll just go to Utrecht or Den Bosch instead.