Most people in Serbia dont think positively about EU.
Maybe they don't think positively about certain aspects of the EU, which is natural - no organisation is perfect, but not the EU as a whole? Besides, people in Serbia might be wrong. People in many countries of the world have been wrong in the past, perhaps it's possible with Serbia too?
Look at pure, simple facts, brate: in 1990 Polish GDP was 65.98 billion USD, whilst Ukrainian GDP was back then 81.46 billion USD (some 20% higher
Ukraine never joined the EU. In 2018 Polish GDP was 585.7 billion USD, and Ukrainian 130.8 billion, which means that our GDP is about 450% higher
That's why, after 30 years of membership, overwhelming majority of Poles vehemently supports our membership in the Union (even if some aspects are not ideal, it is still the most successful international organisation in Europe's long history).
In the pre-accession referendum 77.45% of Poles voted YES to join the EU, with support in some regions reaching well over 80%! Poland never regretted her choice, and even now under PiS government is vehemently pro-EU (not in all aspects, of course).
Now, get this Crow - do I have your full attention? Get this - 30 years since joining the EU, Polish support for the Union didn't fall (as some people falsely claim) - it actually rose substantially to, for example, 91% in March 2019
. 91%, do you get this, brate? Ninety-one-percent support - Poles haven't agreed about anything that much since... since... no, actually Poles have NEVER agreed so much about anything
Currently 89 % of Poles support Poland's membership in the EU: 98% of KO, 95% of New Left, 92% PSL, 89% PiS(!)
and even 77% of Konfederacja voters :D
Of course, the aforementioned growth of GDP can be attributed to Poles' ingenuity and hard-work, but let's be honest - political stability, that EU-membership/pending EU membership gave us, for investments, access to the common market, as well as substantial funds, played an important role as well.