You might end up in jail for criticizing the king in several countries around Europe. In the Netherlands it can get you four months. Only recently has the punishment been reduced down from a five year sentence for speaking ill of the king.
The monarchy is quite popular in the Netherlands, and there was little public appetite for revisiting the old law, with some traditionalist strongly opposed to reducing the penalties. Public opinion polls show the royal family enjoys tremendous approval. Their PR success is partly due to effectively crafting a people-friendly image, and of course managing to not get much public criticism.
The Netherlands isn’t the only country with these kinds of laws, several countries in Europe still have them on the books including Denmark, Norway, and Spain. And it isn’t just kings, criticizing heads of state around Europe can be risky. Germany recently warned its citizens who might visit Turkey to be extra careful for any online criticism of Turkey’s President. There have been a recent spate of cases against Germans for criticizing Erdogan or the Turkish government.