Hailing from the very western most coast of Norway, I can usually understand Swedes just fine. I have three swedish cousins though, but then again, those three are fluent in both swedish and the West Norwegian dialect, due to them having lived here quite a lot. Two of them live here now.
I recall however I was visiting an old school of mine, and had a conversation with one of the new pupils, quite a pretty swedish girl. Suddenly she asked me a question, and I completely misunderstood. As we found out after a painful period of intense thought labour, when she said 'När' (when) I misheard it for the Norwegian 'der' (there) and thusly I looked behind me to figure out what she meant. I felt like an utter gimp in the aftermath.
This wasn't interesting, heh.
Danes? Hrmh. If they speak slowly and announciate properly, I should manage to have a succesful conversation.