Well the difference in language is that spoken Swedish and Norwegian are mostly the same but written Norwegian and Danish are mostly the same. Written danish and spoken Swedish as well.

Danish people believe that they created Scandinavia and Swedish believe the same. Norwegian do too but it's most likely that the Norwegians did it because the "Latin of the North" is called "Gammel Norsk" with means old Norwegian. 

Denmark and Norway are much closer to each other in their mentality and tend to mock with Sweden a lot because Sweden is so close with Finland and Finnish is not a Scandinavian language.

A lot of Norwegians and Finnish people (I don't have much contact to Danish people, they always talk like they got a potato in their mouth) say that Swedish are good at two things: Being pretty and being dumb (I'm not being racist here, that's just what I was told why I can't bring a swedish finn home) most of the time both attributes come together. And at least with the pretty most of the world agrees. 

Both languages and cultures are pretty close in my perception.