Most of our cuss-words are loaned from the proto-baltics. Perkele!
Fits nicely to the topic, as it's not the word itself that makes the difference. It's the intonation.
In fact, it actually works with expletives that are not even Finnish. I speak pretty fluent English with very little to no accent, but when I cuss in that language, I weigh words and sounds closer to my native tongue (such as g-Od-Dam-miT!). Strangely enough, it always gets a jump out of any native English speakers in the vicinity, and they're like "whoa, man, how do you DO that?"
Northern Swedish is very different from Stockholm Swedish. It's extremely monotone and doesn't have those lisping 's'-sounds or round r's that they use in the capital. Stockholm Swedish is the only thing foreigners come in contact with though as that's where tourists go and that's what's on tv. I can't say I'm very happy to be associated with that as it does indeed sound very gay.