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.
Badass Decay: Magma, who starts off as broody and bent on revenge but by the end, he's really just there to be a Quake/Brade Fanboy.
Die for Our Ship: Though no pairings in Spider Riders are 100% canon, of course excluding Mantid/Lorraine there have still been plenty of ship wars, mostly Hunter/Aqune vs. Hunter/Corona and Buguese/Aqune. The Hunter/Aqune side tends to be particularly insane and immature, and Buguese has become especially hated, bashed and mis-characterized (usually as physically abusive to Aqune, or in a mutual hate relationship with her) as a result.
Ensemble Darkhorse: Despite appearing in only one episode especially considering it turns out that she was Beerain in disguise, and the true version doesn't appear until the very end of the episode Noia has quite a fan following among the Japanese fanbase.
Ho Yay: Most the cast is male. What do you expect? Magma constantly clings onto other men, Grey/Slate and Igneous have a little less.
Macekre: The dub included name changes, plot changes, personality changes, and stupid dialogue, which was forced to conform to some very awkward lip flap.
Strangled by the Red String: More one-sided, so it may not count but before episode 35 who could have guessed Beerain was that infatuated with Buguese? Let's not even get into what this does to her character for the rest of the series.
Unfortunate Implications: In the episode "Memories of Champions", Hunter learns of a man who was married to the woman who takes care of the monument. Turns out the man was also a Spider Rider and he left to go fight the Invectids. While the man himself is never seen alive, Brutus gave Magma a Manacle that he had with him so...put two and two togther.