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.
A lot of people are genuinely fond of the anime movie.
The original stories were themselves published in an era when science fiction was regarded as lowbrow stuff unworthy of being called literature, ensuring that any following they had was a cult one, and they're no longer in print today. Nevertheless, in many ways they set the tone for the stories that followed in their wake and continue to attract a modest number of fans to this day.
Genius BonusGalactic Patrol includes a very amusing technobabble explanation for the unlikely properties of one of Smith's favorite inventions, Duodecpylatimate, AKA Duodec, the ultimate chemical explosive. You have to understand scientific notation to figure out the joke. Smith was reportedly delighted to be called out on this "mistake".
Magnificent Bastard - Mentor of Arisia is the king, but honorable mention goes to Nadreck the Palainian, exemplified when he single-handedly defeated a massively defended enemy fortress by secretly manipulating the inhabitants into a civil war that killed them all. He's so embarrassed that his planning and execution wasn't perfect,forcing him to deal with the last three survivors personally, that he only reveals the extent of this "failure" when ordered to do so, and refuses to discuss it further.
It's implied that Nadreck's entire species is like this, except that Nadreck is the most capable of them (and one of the few willing to stick his neck out to perform tasks for the general good- a little). Palainians are among the stranger aliens in the history of science fiction, both physically and mentally, especially if you look at its early days when Human Aliens were the norm.
Come on - what about Helmuth? He at least realised what he was up against and tried to take precautions; had Kinnison not already learned his lesson from an incredibly close brush with death that he was lucky to survive, he'd have been toast.
It is a measure of Kinnison's respect for the man that even two novels later, he would look at a sloppy Boskonian defensive emplacement and go 'You know, Helmuth wouldn't have screwed this one up.'
Seinfeld Is Unfunny: Much like Lord of the Rings is for fantasy, this is essentially the archetype for the Space Opera style of science fiction. Of course, with that comes the fact that so many of the concepts that seemed fresh and new when it was first written have either been explored even further or overplayed in the intervening years.
Serial Numbers Filed Off: The shareware game Children of Arisia takes place on the planet Medon, where the player, a third-level intellect, must fight against the forces of Boskone and the Overlords of Delgon who are attaching humanity via a hyper-spacial tube...
Also, it's taken for granted that libertarianism is the right form of government. At one point, government is loftily mentioned as having been "reduced to its proper sphere and concentrated in the Patrol."
On another note, pacifistically inclined modern readers may be uncomfortable with the Galactic Patrol's willingness to use overwhelming force against Boskone's fortified planets, or feel that they do so without due regard for collateral damage. Whereas the books were written during and immediately after World War II, when the Allies were indiscriminately pouring megatons of explosives over German and Japanese cities and few people found anything questionable in this.
The idea that a human woman could be a ruthless, cold-blooded murderer is seen as appalling and impossible in First Lensman. This is why women Lensmen aren't admitted, except for one who Virginia Samms hypothesizes would have to be some kind of monster; a real Lensman must be a killer. Actually, this one is shown to be incorrect. Clarissa isn't any more ruthless than Virginia; it's implied that the real reason behind the ban is that women Lensmen would screw up the Arisians' breeding programs. Today, the idea that women can't be natural-born killers would be laughed at.