These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Critical Research Failure: There is a city named Trelew in a Spanish-speaking country on the other side of the Atlantic from the one in Cornwall, but it's in Argentina, not Mexico.
Designated Villain: Steve. He's squarely in the position of being the villain, but all he really does that's bad is attempt to persuade Arthur that of the six hundred million kids who've had presents delivered, it doesn't really matter all that much if one of them gets her present a few days later. Apart from that he's intelligent, efficient, takes pride in his job and is even sympathetic, in that he's been waiting and hoping for years to become Santa and is doomed to be cheated out of what could be considered his inheritance. One of the criticisms the film received was that none of the characters were really mean enough to count as bad guys.
According to Word Of God from writer and director Sarah Smith, Steve was never thought of by the film makers as a villain. It's probably due to bad marketing that some got the impression he was intended to be one. (Really, the film in general was marketed all wrong.)
Arthur's breakdown after he, Grandsanta and Bryony get stranded on the Cayo Confites in Cuba. It's almost like as if Arthur stopped believing in Santa, just like a kid growing up would do. Made even worse by Arthur's last line in that scene: