Because of Ashley Tisdale's lovable Large Ham performance, Sharpay comes across as less of an arrogant bitch and more starstruck and neurotic. Her passion for theatre and her determination to be successful also suggests that Sharpay doesn't do the manipulative things she does out of malice - she just truly wants to be the best at everything (star in the musical, dating the most popular boy in school, etc.) She doesn't dislike the Wildcats in the second movie because of any reason other than "they'll steal my talent show!" Selfish, yes, but by the ending of each movie she's realized her mistakes.
In the sequel, Chad and a few other Wildcats come across as overly harsh sometimes when they're unhappy with Troy. See Broken Aesop.
Quite a few fans assume that Gabriella has trust and Commitment Issues about getting close to people. Despite the fact she and Troy adore each other, she's repeatedly thinks he's going to hurt or leave her, and pushes him away in every film because of it. note In #1 he does genuinely betray her so fair enough, but in #2 she leaves over something that was mostly Sharpay's fault and #3 Troy doesn't do anything at all. Then add in that she has a Disappeared Dad, was ostracized at her previous schools and apparently never had a permanent home (living somewhere longer than a year) and she borders on Broken Bird.
Gabriella: I'm a lot better at saying goodbye than you. I've had a ton of practice.
Likewise, Troy seems less like an uber-popular Big Man on Campus and more of a Broken Ace worn down from years of being East High's golden boy. Every film has him breaking down over disappointing his Dad or friends, often while Chad and the wildcats sit there criticizing him. His delight at Gabriella liking the "real him" makes you wonder when he'd last been allowed to just relax. One tumblr post argues him attending Berkeley was less about Gabriella and more about escaping everyone's expectations.
This tumblr user sees the romantic relationship between Gabriella and Troy as an emotionally abusive relationship - with Gabriella as the abuser. Their best arguments can be found here (which contains links to their other arguments) and here, as well as in the tags of various things the user reblogs.
Big Lipped Alligator Moment: In the second movie Sharpay tries to get Troy to perform "Humuhumunukunukuapua'a" with her, an extravagant Hawaiian themed number about a pineapple princess and a fish prince falling in love. Characteristic of Sharpay, this is a huge production number with backup dancers and Ryan narrating, providing sound effects/fog, and playing the ocean and fish. It makes just as much sense in context and is never brought up again or acknowledged in the plot. No wonder it's not in the Disney Channel airings, but limited to the home video release.
It may be seen as this in universe as well. Throughout the number, we get repeated cuts to Troy, who's facial expressions likely mirror that of the audience.
It is actually brought up one more time when Sharpay demands Troy and Gabriella's duet from Kelsi. Ryan, who was just kicked out of the talent show by his own sister ask what'll happen to Humuhumu and what he's supposed to do with his Tiki warrior outfit.
High School Musical 2. Some saw it as a step in the right direction but many people pick up on a lot of issues, in particular the Informed Wrongness of Troy's decisions (how dare you miss a baseball game to work for a scholarship!), the Family-Unfriendly Aesop of the wildcats' reactions (focusing on the future is bad), Sharpay taking a ridiculous level in jerkass, and most of all it's not even set in high school!
Sharpay's Fabulous Adventure. It's not a musical, and even factoring that and its spin-off status in it has a completely different "feel" to the other movies. And those are the minor points - it forgets that Sharpay was supposed to go to the University of Albuquerque after graduation and that Ryan and Kelsi went to New York (they had to rush just to get Lucas Grabeel into the movie at all, so much that his scene is only in the broadcast version).
Some people feel this way about Sharpay and Ryan, at least in the first movie. They have been doing all this musical extravaganza for most of their life and then in waltzes two people who have never actually sung seriously a day in their life and they easily got shooed in to get the parts. Although they can be pretty mean at times (especially Sharpay) you can at least understand why they would be pissed off.
Averted in the second film where Sharpay is a lot more mean-spirited, has no sympathetic justification for stealing Troy away from Gabriella, and treats the rest of the characters like dirt. The third film gives her more understandable motives again, as all she really wants is a decent chance of impressing Julliard, even if she goes overboard trying to get there.
Ear Worm: Every Song. Especially in the first movie.
Epic Rocking: "Work This Out" in the stage version, and to a lesser extent, "Bet On It". Oddly, "Bet On It" is actually less Narmy onstage, partly to the fact that it becomes more of a Massive Multiplayer Ensemble Number with more emotional weight and less interpretive dancing.
Fan-Preferred Couple: Although Troy/Gabriella is still the most popular pairing in the fandom, there are more people who also ships Troy with Sharpay than those who ship her with her canon eventual partner, Zeke.
The "Star Dazzle" for most popular (sadly non canon) ship would probably go to Chad and Ryan who have a very dedicated following. On AO 3 alone they have over 200 works wheras Troy and Gabriella have...44. Let that sink in.
Family-Unfriendly Aesop: The second film has several, the worst one being that hanging out with your high school friends is more important than your whole future. Troy is portrayed as the bad guy for missing a few ball games because he's trying to get a scholarship and earn money for college. He's redeemed when he throws away chances of impressing the College board so the other wildcats will be friends with him again.
Technically the whole problem was that he was forgetting dates and leaving his friends standing in the dust despite there being enough time to tell them beforehand that something else came up. He never actually did say "Hey guys, I'm sorry but this is important" when there was still time for the others to change their own plans. He didn't acknowledge them in any way to the Red Hawks either even though Chad was right there so if one thinks about it, the aesop isn't all that family unfriendly at all. Thinking about the future is not bad as long as you don't forget about the present.
Even among non-Ryan/Chad shippers, general fanon is that something went down in the locker room after the staff baseball game in HSM2.
In the same vein, Ryan being gay has been pretty much accepted as fact among fans, usually accompanied by a handwave that Kelsi is just a beard. Surprisingly few people consider the option he might be bi.
Gabriella's mom is nameless in the films, but is usually Isabella or Maria in fanfic.
Ryan being dyslexic is brought up in at least 75% of fanfics where he has a lead role, most likely based on him being unable to read Go Drama Club in the first movie.
Freeze-Frame Bonus: Miley Cyrus is among the dancers in the closing number of High School Musical 2. She gets a very brief closeup towards the end.
Also seen dancing at the HSM2 conclusion is ShaneHarper.
Harsher in Hindsight: Matt Prokop's scenes in HSM 3, considering the revelation of his abuse towards his girlfriend Sarah Hyland and the fact that they met while auditioning for HSM 3 become much more uncomfortable to watch.
Everything about the "I Don't Dance" sequence in HSM 2. The next time we see Chad and Ryan, they've switched clothes. General consensus among fans is that the entire song is about Chad being in denial about his sexuality and Ryan encouraging him to just let go.
HSM3 has Troy practice a dance move, which he and Sharpay was supposed to perform together, with Ryan. When he was asked to actually do the move with Sharpay, he complains that Ryan was the better partner.
Hype Backlash: People that didn't enjoy the series were getting sick of all the attention it got, especially when its soundtrack blared in anything that had a speaker.
It's practically impossible to watch "Bet On It" without at least cracking a smile.
"The Boys Are Back" from the third movie.
"Scream", also from the third movie. Basically "Bet On It" with a bigger budget that was not at all. The titular scream that ends the song could not be more wooden.
Narm Charm: The series in a nutshell. It's ridiculous, corny and twee...but it was insanely popular for a reason.
No Problem with Licensed Games: The games are pretty good, but only because of what gameplay they’re based on. The first two games on DS use the Elite Beat Agents/Osu! Tatakae! Ouendan gameplay, while the third DS game uses Gitaroo Man's gameplay. The console High School Musical 3 Dance! game also uses DDR gameplay on dance pads (On Wii, it's Wii Remote and Nunchuk). While it's somewhat simplistic in terms of difficulty, it does serve as a decent rhythm game. Unfortunately, all the games use covers, which is ironic since Disney develops the games and made the movies. The Game Boy Advance game based on the first movie does have it's own merits too, despite being one half platformer, one half rhythm game.
Surprisingly Improved Sequel: Between a better budget, more production time and the adorable chemistry Troy and Gabriella have developed through Zac and Vanessa's Romance on the Set, Senior Year is probably the best of the three films. Not to mention Troy and Gaby's relationship gets some depth, as per their confiding in each other about their fears for the future.
Each sequel got better in terms of budget and production, with the first one looking much less cinematic than the third.
Special Effect Failure: The second movie, during the song "Bet On It", has Troy looking into the water of a pond, showing his reflection. Ignoring the obvious CGI effect, the reflection itself was not mirrored.
Off-screen, but in the first movie a character says brother and sister Ryan and Sharpay played the title roles of Romeo and Juliet.
The fact that the theater director seem to have no issue with a brother and sister playing romantic interests.
Not only that...but the school administrators don't seem to notice this.
Strangled by the Red String: In a badly-made excuse to stop the rumors that the character is gay, Ryan was paired up with Kelsi in the third movie. They are good together, if you ignore the fact Kelsi was paired with Jason in the first two movies and the insane amount of flirting between Ryan and Chad in the second movie (which was intentional).
'Right Here, Right Now' in the third film as Troy and Gabriella consider their future apart from each other. The cut reprise version - set after they've said goodbye - is even worse.
The finale for the third movie has the cast end the song jumping in front of a literal Title Drop. Then we get a close up of each of the character's faces. There's no dancing, no singing, just them standing there smiling, before taking a company bow. It seems awkward at first, but then it hits you: this is their curtain call. These six talented actors are saying goodbye to their characters, and to us. It's a subtle, but effective, instance of Leaning on the Fourth Wall
The lyrics of the song ("High School Musical") don't help either, especially when you consider that out of the main cast only Zac Efron and Vanessa Hudgens really went on to have successful careers.
Vanessa Anne Hudgens seemed to be contractually obligated to sing one overly emotional break-up ballad each movie.
Zac Efron became obligated to supply one token emo, narmy song per movie, famously including "Bet On It" consisting of Zac Efron interpretive-dancing angstily through the golf course in what's supposed to be a serious moment.
"NO, NO, NO, NOOOOOOOOOOOOOO. STICK TO THE STUFF YOU KNOOOOOOOOW."
The Woobie: Gabriella's backstory: It's implied her father has passed away and her mom's constantly-moving job meant she never settled anywhere. Plus she struggles to make friends because of being labelled the 'freaky math girl' wherever she goes.
Troy in the third film. Everyone around him is pressuring him to do different things, he has no idea what to do with his life, and his girlfriend - who he admits was the one person who doesn't see him as the perfect basketball boy - is leaving.