Exactly, seriously why is everyone in Spain like this? Spain is a wonderful and advanced country in most ways. Although I think having an inferiority complex is probably good for the country because it's the only way to improve.
National identity is a social construct. Spain has always been the sum of several national identities. This has of course created frictions, but there wasn't the push that order countries had to eradicate those identities when the birth of most modern states happened.
Franco tried to change that (as well as eliminating a sizeable part of Spain that didn't fit with his values). To this day, many spaniards identify the spanish national identity with those Franco's values (despite being fairliy minoritary and Spain a very socially progressive country).
After the transition to democracy, regional governments had a lot of incentives to create or reinforce their own identities to gain economic leverage against the central government. This has always been extremely transparent and it's no coincidence that the two richest regions have the strongest independentist movement.
So yeah, there is a lot of self-hatred or internalised inferiority complex... But also dishonesty. Many of the comments you will read online are self-interested (catalonian independentists) or even straight propaganda from the catalonian government. Not that it would be hard to find any other spaniard to rage about how Spain is, actually, a 3rd world country.
Nah, not everyone. You will see all this people singing proud "I'm spanish!, spanish!, spanish!..." in the next UEFA champions league. I assume that we are just a little drama queens sometimes, but in the end we all are very similar to you. You will find exactly the same frolicking behavior in any basketball league.
Being young adults and trying to thrive in a big city is not easy of course, but this is not a problem exclusive from Spain
