There are certain things that I have issues with like that, too. Få isn't too tough for me, but även and nog are two words that I have issues with for one reason or another.
The three verb politeness is kinda funny, I always feel a little weird about it. My girlfriend always accuses me of being too straight forward, but I think that has to do with the fact that I don't add verbs for politeness because it feels unnatural. Though, honestly, I'm getting way more used to it now. "Skulle jag kunna få..." or "Jag skulle vilja..." But, I have to say, in English we have some pretty winding politeness rules as well. You gave the example of "I would like..." but depending where you are, that's actually even considered kinda rude. Instead you ask questions instead of making demands, like "Could I please get a glass of..." Despite the fact that the person working at a restaurant or bar is there to serve you things, it can still be considered rude to not break out the "questioning demand." My mom used to do that to me when I was a kid. She never ordered me to do things, instead she would politely ask me to do everything that was required of me, as though I had a fucking choice.
We worked out one time in class that you can get up to 5 verbs in a sentence in Swedish, but I forgot how you would do it.
People ask me about the hardest part of the language, and I think en or ett is probably the toughest thing. From those things you get all other information in a sentence, so that whole noun, adjective agreement thing can get really tricky and frustrating. I'm constantly checking up words, 'cause I hate sounding like an idiot. I've gotten pretty good at knowing what's what, but I'm sure I still make mistakes from time to time.
Another thing that is a total bitch is definite and indefinite. For me, the issue is not bordet or borden, but instead, when one uses definite and indefinite. For example, in English we tend to make abstract things "abstract" by not adding the definite article. So in English where one would say just "society" in Swedish one says "samhället," or "the society," or instead of saying "suicide rates" they say "självmordsstatistiken" or "the suicide rates" all the time, despite it being general and you're not necessarily referring to one specific instance or study (this is probably a bad example as I'm coming up with counters right now off the top of my head, but you get the gist of what I'm saying). There are, of course, other examples of this as well when talking about politics, or the government and so forth. Where I would use indefinites or no article, Swedes use definite articles. It drives me fucking crazy sometimes because it seems so absolutely illogical to me. The problem is, of course, that I am a goddamn psychotic perfectionist about this kind of stuff. I believe this comes from being monolingual and never really being forced to struggle through a language until now, but I hate, hate, hate, hate, hate, hate, hate sounding stupid and I hate saying things wrong. And Swedes are all too damn polite to correct you, so you can walk around saying shit wrong for months before some drunken dude finally has the balls to tell you that you're saying something wrong.
I tend to make up this frustration by laughing at Swedish how say "wiking" instead of "viking" in English. Despite the fact that the V sound is exactly the same in Swedish, they still manage to fuck it up. It blows my mind.
Also, fun tip: if you spend a lot of time with Swedes, listening to their mistakes and translating them back into Swedish is a very good way to pick up things that might commonly be mistakes. For example, they regularly say "on the pub" instead of "at the pub." Well, that's 'cause they say "På pubben." My list of svengelsk mistakes is quite long, because Swedes are really pushy about speaking English with native speakers.
On the thing about plural: very good way to think of it is that often times an "a" ending leads to an "or" plural (flicka-flickor, Annika-Annikor). Single syllable ett words often have no plural (hus-hus, bord-bord). But those rules don't always hold. You basically have to learn words by each word, and that's a pain in the ass, but so it goes.