Stupidity: The decisive goal happens merely because the players pass the ball to the opposition instead of clearing to the wings. Reading poorly the situation happens in real life as well, but here we have a group of 4 players who charge in close formation, and with all the rest of the field at their disposal, the two Nankatsu players pass the ball in the middle of them for no reason.
Stupidity: In any normal match, 4 players who deliberately charge the keeper and hit him when he already has possession would be sent off or booked, here of course it does not happen. What's more puzzling though, is that the team had as deliberate strategy to injure the keeper, they are shown with evil eyes and grins like homicidal maniacs...but then at the end of the match they exchange pleasantries, handshakes and sincere goodwill wishes.
Stupidity: Genzo suffers a possibly career-ending injury to his ankle. He goes to the doctor for that, and the doctor talks to him, and they discuss this important matter...without his parents or a legal tutor, teacher, coach (there's nobody present at the visit, and he walks out of the hospital on his own). He's eleven years old. His personal coach that follows him anywhere is nowhere to be seen in this episode, obviously because it would detract from the drama if he were around to explain stuff to Genzo's teammates or the main Nankatsu team coach.
Stupidity: Roberto Hongo is the center forward of the Brazil national team, and as we see from Tsubasa's poster/magazine, he did not alter his appearance except for wearing a fisherman hat sometimes. Despite being surrounded by football fanatics, he manages to keep a fairly low-key profile and it's totally not a big deal to have a top tier footballer hanging around the small prefecture.