There's not rivalry between Swedes and Finnish apart from:
1. Ice hockey. Both parties think they're no.1 in the world and both parties get pissed off when the other one wins in those cases Sweden-Finland eventually meet.
2. Finnish despise Swedes. Mostly because there are Finland-Swedes living in Finland (Linus Torvalds is one of them, btw).
3. Finnish think that all male Swedes are gay. Huge stereotype ofcourse, but widely spread. It's no problem though, because...
4. Swedes think that Finnish are all drunks, sitting in their fancy sauna and bathing all day long.
5. Swedes think that Finnish is a uncomparably hard and ugly language... the opposite applies too, though.
All of this doesn't stop the Swedes taking the Helsinki ferry every weekend and get stoned and heavily drunk, which ofcourse, are joined by Finnish that actually take the Stockholm ferry (same boat) to do exactly the same thing
After all, what unites us is sex and alcohol
That's a rundown of the feelings around here.
My own experience ( and only one) with Finland has been a fine for 300 mark for "disturbing the peace" at 5 AM on one of the above mentioned ferry trips.

Not only I had to pay the cash, but I had the honour to accompany the nice Helsinki police in their car to inspect their quarters. And no, I wasn't drunk

PDAFantast.