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.
Is Silva a Tragic Villain and Woobie, Destroyer of Worlds, or a childish monster who is the victim of his own behaviour (since M only sold him out because he was hacking the Chinese without authorization). On the one hand his Trauma Conga Line was pretty nasty involving torture and betrayal; on the other though, he commits a staggering amount of murders and engineers a terrorist campaign solely out of petty revenge against one person, and the Offstage Villainy he alludes to is implied to be even worse, funding a decadent lifestyle via crashing financial markets, orchestrating terrorist attacks or causing and faking disasters.
Similarly, there is disagreement about Silva's Evil Plan. While its obvious he intends to humiliate and then kill M, did he always plan on it being a murder-suicide or was killing himself simply the end of his Villainous BSOD, since Bond had foiled his original scheme and then proceeded to kill everyone in his organization, and M had already been fatally wounded by an underling despite his orders (albeit before he actually issued them).
Angst? What Angst?: Bond doesn't seem too concerned when Severine is shot, despite saying he'd protect her.
Nor does he react strongly to the destruction of his childhood home where his parents died. Most jarringly, there's a secret tunnel where young Bond hid for 2 days after the death of his parents. Not only does Modern Bond enter the tunnel without the slightest hint that it holds any special meaning to him, but he outright states "I always hated this place".
Eve is horrified when she initially "kills" Bond. But by the time he comes back from the dead, she seems to have gotten over it.
With the time frame between Bond's "death" and return she had proper time to grieve over it and she did mention that she was considering taking a different profession since she still expressed guilt over the incident.
Award Snub: After serious, genuine hype about the possibilities of Oscar nominations for Dench, Bardem, as well as Picture and Adapted Screenplay, the film garnered no nominations in any of the big categories. On a more positive note, Skyfall received nominations for Best Song (which it won), Best Score, Best Sound Mixing, Best Sound Editing (which it also won) and Best Cinematography for Roger Deakins. It's actually more Oscar nominations for any Bond movie ever—beating out The Spy Who Loved Me.
The British awards (BAFTA) does a bit better with their Best British Film nomination and includes supporting acting nominations for Dench and Bardem. Director Sam Mendes still gets snubbed. BAFTA has no Best Song award. On the other hand it won the BAFTA for the Best British Film, the first Bond film in 50 years to do so.
Adele's theme Skyfall, which incorporates the James Bond theme and foreshadows numerous events in the movie. It became the first Bond theme to win the Oscar for Best Original Song, said Oscar also being the first for the entire franchise since 1966 when Thunderball won Best Visual Effects, and the first for an actual performance and not a technical award.
"Boum!" by Charles Trenet, which is played during Severine's execution.
"Boom Boom" by The Animals, which is played when Silva shows up in the helicopter.
Big Lipped Alligator Moment: Silva pulls out his false teeth to show M what cyanide does to a person. The disfiguration is effective Nightmare Fuel, but once he puts the false teeth back in, it is never so much as mentioned again.
Broken Base: While the movie was a massive critical and commercial success, ironically diehard Bond fans tend to hate it. There's a variety of reasons for this (no gadgets, a completely joyless and ineffective Bond, the villian's relatively mundane plan, the third act that's basically just Home Alone, the child-prosititute turned Bond Girl (and the way Bond lets her die), the destruction of Bond's classic Aston Martin), but most of them contribute to the greater issue that the movie often feels like it's going out of its way to mock and belittle old-school Bond and his fans; in fact, one of the themes of the movie is that Bond himself is an outdated, useless concept... which, sure, could be an interesting idea, but probably less so to people who just paid money to watch a James Bond movie.
James Bond stands by and patiently waits while an assassin kills a politician, puts some incredibly creepy moves on Severine and and kills the villain, a failure since M's stated preference was for him to rot in prison. The only positive thing that can be said is that he survives. In a sense this is exactly the way Ian Fleming first conceived of Bond.
M. Too often, she harms the lives of herself and her agents for unnecessary risks rather than trust them to sort the problem out. In the pre-song scene, she orders Eve to shoot, risking Bond's life in the process, even though Bond still has a chance to defeat Patrice. Later, when she is warned of Silva's escape, instead of doing the prudent thing by aborting her hearing, she proceeds with it, in effect endangering a bunch of top notch Member of Parliaments and government officials and God knows how many civilians for her personal pride.
Her own death could probably have been avoided had she simply apologized to Silva at their reunion, as evidenced by the fact that he ultimately could not kill her once he saw her vulnerable.
Harsher in Hindsight: In Casino Royale 2006, M states she is considering selling out Bond for shooting up an embassy. Since the events of Skyfall contain a reveal that M willingly sacrifices even the best of agents without hesitation, the line carries a far greater weight when you know what she's willing to do.
Similarly, M tells Bond "Orphans make the best recruits." in reference to his own past. However, in GoldenEye Alec Trevelyan was an orphan who blamed England for it, and that formed his key motivation.
Jerkass Woobie: Silva by the later parts of the film. Most notably towards the end when he cries over M being mortally wounded.
Like You Would Really Do It: Bond "dying" during the opening sequence. Notably, the "reveal" that he survived is treated with an offhand casualness that shows the filmmakers were well aware it wouldn't hold any tension. Subverted with M's death in the end.
Magnificent Bastard: Silva. If you do anything in the film, he planned for it and knows how to work it to his benefit.
Shipping: Kincade and M are friendly to each other when they meet, they both have the Parental Substitute thing going on, and their actors are around the same age. Granted, any possibility of anything going forward is destroyed by the fact that M is dead.
So Cool It's Awesome: Is already the highest-grossing Bond film and is already being counted among the best of the series.
Special Effect Failure: The shot of Bond going over the waterfall would be a lot better if it hadn't been so bloody obvious that it was a dummy.
Bond staring at the (obviously CG) Komodo dragons in the midst of a fight makes one think he also found them to be absurdly out of proportion. Likewise, the scorpion in the bar scene toward the beginning is poorly composited against Bond's hand.
They Changed It, Now It Sucks: Some fans were unhappy about Sam Mendes' longtime collaborator Thomas Newman serving as the film's composer instead of regular Bond series composer David Arnold.
They Copied It, So It Sucks: Other fans were unhappy about how the second act resorted to copying The Dark Knight, after setting up a pure, classic Bond thriller in its first act. What's odd is that there are several other works with similar elements to that second act.
Some fans, and Screen Junkies, have unfavorably compared the use of homemade traps during the showdown at Skyfall mansion to Home Alone.
They Wasted a Perfectly Good Plot: Specific mention is made of Mallory being a captive of the IRA for three months, but nobody ever draws attention to how he still serves England and Silva became a Fallen Hero under similar conditions.
It's likely Fiennes will return for a sequel, they're not done with the character yet.
It's more likely that the comparison was supposed to be between Silva and Bond. Both were sacrificed by M for the sake of a mission. Yet Bond, despite his anger, came back and fought for her (and with her), whereas the embittered Silva plotted her downfall.
Unfortunate Implications: Some viewers have called a What the Hell, Hero? after watching Bond's seduction of Severine. Mendes likely never intended to have it interpreted as such but, given Severine's background, there's a strong possibility that when Bond initiated sex she may have felt like she had no choice in the matter. Cinema Sins hangs a lampshade on the discomfort.
Skyfall also became the highest grossing James Bond film ever, grossing $1.11 billion, ranking as the 8th highest grossing film of all time, which includes $304.4 million in the United States alone.
It is also the highest grossing film of all time in the United Kingdom, earning $161.2 million there.
The Woobie: Severine, so very much. For starters, it's implied that she's been a Sex Slave for most of her life, and has been getting abused for who knows how many years by this point. Then, she finally finds someone like Bond, who can potentially set her free from this life, but shortly after taking him to Silva as requested, she ultimately gets unceremoniously shot in the head by Silva himself, and Bond is by now, too desensitized to death to even mourn her. The more one thinks about it, the more of a downer it really is.
Worse, Silva planned on getting captured. For that he needed Bond brought to him, meaning Severine actually did what her sadistic boss wanted. And still, he shoots her.
It feels much more likely that Silva's plan for getting out of MI6 after his capture was a backup, in the event he was captured while interrogating Bond. Hinging your plan on having Q plug the laptop of an established master of digital warfare and espionage directly into the MI6 mainframe with no regard for whether the tantalizing package of data Silva had with him, secured enticingly using a system Q invented, could be a trap doesn't seem like the best idea in hindsight. Having the bait there makes for a better safety measure than a natural step in an evil scheme.