I've visited Serbia a few times and I honestly don't even realize if these people need to join the EU.
I really found here everything I needed and even more I was lucky to find great people everywhere, very hospitable people, always ready to help you.

Look, just now I remembered a situation, I was in a public parking lot (with difficulty I found a free parking space) and actually I couldn't pay the parking by phone, I didn't have a Serbia phone number, two young people who were there in the parking lot saw us that we wanted to pay parking and we could not, so they asked us if we want to help us with the parking payment, of course we accepted (the parking payment was made from their cell phone) and so we managed to have parking for a few hours there.

When I wanted to pay them in cash the amount they had paid from their cell phone they didn't accept our money, they simply said that they wanted to help us not to get a fine.

Have a great week ahead!