Full disclosure, I was born in Sweden but moved with my parents to the US when I was 4 and lived in the US until I was 17, and now I am 21 and have lived in Sweden for the last 4 years. My parents were both born in Sweden as well but they are of North African descent. I consider significantly more American than Swedish since that is where I lived most of my life.

Note that everything below are just my opinions obviously.

1. In Sweden people do not waste as much money and buy as much shit as we do in the US. They are much more conservative with their spending, but that is not to say that they are cheap. They just don't waste their money as much like we do in the US.
2. In Sweden its extremely difficult to make friends with natives if you aren't a native Swede. Even if you work your way through the Swedish language and become fluent in the language, you will be considered an outsider. Even if you do end up making some Swedish friends, often times you will be seen as the "second option" or an acquaintance more than a friend so to speak. It also becomes much more difficult to make friends depending on the color of your skin. Sad but true. Overall there is quite an anti-immigrant sentiment in Sweden and if you aren't white it will not be in your favor in my opinion.
3. When it comes to learning the language, Swedes typically do not want to speak Swedish with you unless you speak fluently or at a native level. They will often times to switch to English if you mess up a verb conjugation, en/ett word, have an accent that doesn't sound like a European accent, etc.
4. Living paycheck-to-paycheck is quite common in Sweden. "I ran out of money and am waiting for the next pay period" is quite a common sentiment here. This one was very strange to me to be honest.
5. Most things are very unorganized in Sweden compared to the US. The only exception I can think of are the social services. The social services are quite organized. But things like gymnasium and university education are fucking complete shitshows. Occasionally this will be to your benefit. For example you can finish some university courses literally months after the course has already ended and the professor and TAs will still grade your work and pass you.
6. Racism is very common here overall which I despise. I am personally not a fan of discrimination based on race.

Here are some more positive things:

1. Public transit is extremely good here to the point where a car is often unnecessary.
2. Highly subsidized pre-school for kids, free secondary and tertiary education for citizens and permanent residents (including lunch in grundskola and gymnasium) are all great!
3. Food is much higher quality than in the US. I get sick much less from eating out here in Sweden which is fantastic.
4. People are very secular compared to the US. The people who are Christians are not extremists like many evangelical Christians in the US.