There are several reasons Swedes do not like the Danes. One big reason is that the 2 countries have been at war with each other 13 times since 1468. In war there are no winners but Sweden have won 10 times and the coward Danes only 3 times.
Denmark tried to invade Sweden and all school children learn about the cruel Stockholm Bloodbath in 1520. The kids are told about the evil Danish King Christian II (who after the carnage became known as Kristian Tyrann in Sweden). With the support of canon law, the Danish king executed nearly 100 people by decapitation. Anyway after this incident Gustav Vasa took power over Sweden and through out the evil Danes.
Karl X Gustavs famous march with the Swedish army during the little ice age in 1658 during Karl X Gustavs first Danish war. Denmark was forced to submit to Charles X’s will, which led to the Peace of Roskilde. Charles X is said to have said, “Now you, Brother Frederick, let’s talk in good Swedish.”
Another reason Swedes hates Danmark is that the Danes are completely unreliable, their country is built on mud and they have no mountains. There have been more than 100 football matches between our national team which usally ends up with Sweden as winner. To be fair – we love to hate Denmark!