Roughly half of the show follows the development of Vince's passion project, Medellin. It's first introduced in early Season 2, before becoming the direct cause of most of the drama in Season 3 (which should be noted had an 8 month long gap in the middle and was twice as long as every other season of the show) and Season 4, whilst Season 5 is about rebuilding Vince's career after the film bombs.
The "Vince fires Ari" arc in Season 3 - it takes most of the second half of the season to resolve.
Eric and Sloan's Will They or Won't They?, which rubs from late Season 2 all the way to the end of Season 8. And then happens again in the movie.
Vince's Season 6 "plot" of just standing around waiting for his next film to start shooting.
Vincent Chase. While he still has some fans for him being a Nice Guy to his friends, he also has a lot of detractors who dislike him for being a Vanilla Protagonist whose supposed "acting talents" come off as Informed Ability.
Eric 'E' Murphy. Some like his snarky know-it-all attitude and role as the Only Sane Man to balance out the eccentric attitudes of the rest of the cast. Others dislike him for this same reason, finding him the least fun part of every episode. Not to mention his constant Will They or Won't They? subplot with Sloan, which occupies the entirety of the series since Season 2.
Broken Base: The series has always received plenty of flack for its treatment of women, who usually are portrayed as some form of sex object, and the number of times women speak to one another in the entire show is 8.5 times. To some, this makes the whole show some male fantasy trip, to others it... makes the show a male fantasy trip. It really depends on if you can hold on to the notion that the show is a parody of the shallow Hollywood lifestyle.
Crosses the Line Twice: Practically everything that Ari Gold says. His insults come off as so blatantly offensive and tasteless that it comes off as funny in a morbid kind of way.
Mrs. Gold:(reading off a tabloid) After a staff meeting, Ari threw a stapler at the wall and screamed at a fellow agent that he needed to climb back inside his mother's vagina and cook a little longer.
Ari Gold quickly became one of the most popular characters in the show and gained more prominence during the second season. Many consider him to be the sweet saving grace of the show and why some fans continue watching it in the first place.
Eccentric and temperamental director Billy Walsh was also quite popular with fans of the show.
Fan-Preferred Couple: Many fans wanted Ari to stay with Dana Gordon and not go back to his estranged wife.
Ari's admonitions of pretty much everyone usually involve something sexual.
Ari: That was a great speech, Lloyd. Yeah, if I was 25 and liked cock, we could be something.
Fridge Brilliance: Many people have noted that despite Vince being the "alpha" of the group, he's the least interesting of the main characters. But then you realize that the show is called Entourage for a reason; it's more about Vince's friends than Vince himself.
Vince literally gaslights Mandy Moore and tries to get her fired because he feels slighted by her romantically. This becomes uncomfortable given the circumstances of the deterioration of Mandy's own marriage in real life.
Ari's constant misogynistic verbal abuse towards his female employees comes off like this in light when his actor Jeremy Piven was later accused of a number of sexual misconduct situations (several of which allegedly took place during the time he was starring in the show), which just adds to the general unease of certain elements which have aged badly.
After Ari's abusive nature is exposed in Season 7, Jeffrey Tambor swings by to offer support, stating that he's "No stranger to scandal". Ari comically asks "Oh really? What scandal?", leading Tambor to stammer about "Oh there was an incident on Arrested Development. No reason you would have ever heard of it". The gag is supposed to be that Tambor is a boring goody two-shoes who would never be near scandal. Many years later, Tambor's career would be destroyed by multiple accusations of sexual misconduct, and would be infamously accused of repeatedly screaming at his Arrested Development co-star Jessica Walters (with the abuse so bad that Walters broke down into tears just remembering it, and the Arrested Development cast going into civil war). Suddenly Entourage feels like it was grimly predicting Tambor's downfall for comedy.
In Season 2 (Airing in 2005) Vince is originally opposed to the idea of playing a superhero, worried that he'd just wind up in a campy film like Batman Forever or Batman & Robin. A few years later, roles in superhero films started to become much more sought after.
Ari's remark about NBC when Drama's worried they might cancel his new show, Five Towns.
Ari: They gave Joey two seasons, NBC don't cancel shit.
Ari ridicules Peter Dinklage repeatedly (even mocking his height directly to his face). While notable as an actor in 2005, Dinklage would become universally loved the world over (and rake in countless awards and become extremely wealthy) when he got to star in "Game of Thrones" just a handful of years later. Ari probably wishes he'd been nicer to what could have a hugely profitable client,
Years after the show joked about an Aquaman movie directed by James Cameron, an actual Aquaman movie directed by James Wan began development for the DC Extended Universe. Even funnier is that Aquaman will be made in part with the technology that James Cameron developed for the Avatar sequels, which was made to film underwater.
This also means that in the Entourage universe, the DC movie universe Aquaman would be another film franchise getting a reboot in the 2010s. And when one considers Aquaman's use as an Expy for the Spider-Man film that James Cameron almost directed, it's rather fitting considering that the Spider-Man films have been rebootedtwice.
Funnier still, Aquaman, as of January 2019 broke all box office records for a DC-based superhero (even The Dark Knight) movie, meaning the show was more prescient than mocking.
Patty Jenkins directs a couple of episodes, one of which features a storyline of Warner Brothers being completely overwhelmed with happiness due to the success of a fictional DC movie. Jenkins herself would no doubt experience the same gratitude from executives after Wonder Woman was a huge success for the studio.
In season 6, Iris West is Reverse Flash's assistant. Which gets even funnier when one realizes that it isn't really that far removed from what Reverse Flash actually does in the show's first season.
Aaron Sorkin makes a memorable cameo in Season Six where, in a desperate effort to sign him, it's suggested that Sorkin move into directing. Sorkin immediately brushes this off, flatly stating "I don't wanna direct. I'm a writer. I like writing. I could have directed hears ago if I wanted to". Nearly a decade after this episode aired, Sorkin would indeed move into directing with Molly's Game. Additonally, Sorkin appeared to enjoy directing a movie so much that he's transitioned into that frontier. So maybe Entourage convinced him? (But probably not)
Jerkass Woobie: Ari becomes one in "The Beginning Of The End" - When Mrs. Ari tells him that she's started seeing someone else, he looks utterly crushed.
Retroactive Recognition: In the Season 6 episode "Amongst Friends" (2009), the gang is attending the premiere of Martin Scorsese's new film, Gatsby. Eric and Sloan decide to go there as just friends, while Johnny turns up with his date for the day. The buddies rent a limousine for the occasion and Vince is accompanied by a very beautiful model named Lisa, who's played by Gal Gadot, a few years before she became a bona fide star by playing the DC Extended Universe's Wonder Woman.
The character of Dom, whom most fans found to be obnoxious and unfunny. He was intended to become a permanent member of the cast but was quickly written out of the show because the fans hated him. He's also this in-universe in his debut episode, humorously, with Eric, Turtle, and Drama unable to stand his presence.
Ashley, Eric's crazy stalker girlfriend from Season 6 is widely disliked by fans of the show.
In season 7, Vince begins dating real-life porn star Sasha Grey. Many fans loathed her character as well as the entire story arc of Vince's descent into a world of Hookers and Blow.
It's debatable, but complaints about the show going downhill surfaced somewhere around season 3.
Many fans have agreed that season 7 is the show's lowest point, criticizing it for losing much of its warmth and humor and becoming a Darker and Edgier drama. As a result of the fans' complaints, Season 8 returned to a tone more in line with the earlier seasons, with a greater focus on humor and heartwarming moments.
Strawman Has a Point: Verner Vollstedt may have been trying to get Vince to quit Smokejumpers, but he makes legitimate points about Vince's acting and forces him to step up his game.
Unintentionally Unsympathetic: While Ari Gold's Jerkass nature makes him an Unsympathetic Comedy Protagonist, his main redeeming quality of his extreme devotion to his wife ironically makes him fall under this trope. This devotion ends up coming off as clingy possessiveness, with Ari often treating her with contempt and boasting behind her back about various affairs (that admittedly probably never happened). Despite her wishes for therapy, he treats their sessions as a cruel punishment and frequently blows them off. He never refers to her by name, often mockingly calling her "Mrs Ari Gold". He reacts with undue rage and disgust when she has the gall to restart her abandoned acting career in a soap opera and makes out with a male costar in a scripted scene. Mrs Gold is seldom portrayed sympathetically, more often than not, she's shown to be nagging and hindering Ari when he has some vital storyline that needs dealing with. Ari is so completely obsessed with his wife that he develops a season long breakdown when she leaves him, and while the show treats him as the hero trying to win her back, given his literal years of neglect, it has some fairly ugly implications as to how toxic his love for her really is.
Homosexuality is often ridiculed (most notably in an episode where Drama thinks his masseuse is sexually attracted to him and generally reacts with rage and horror.). An entire episode is devoted to the gang's horror and confusion at a homosexual sex act inserted into one of Vince's scripts (turns out the director just wanted to make sure Vince trusted him, he'd never make Vince pretend to do that).
Transgender people are mocked as being ugly. Notably in an episode where Drama attempts to woo a politician by taking him out, and the politician forms a romantic connection with an attractive woman. Turns she's a transgender woman and while the gang are laughingly horrifed, the politican dates her anyway, only to be fired from his position due to this in a punchline gag.
Women are either a revolving door that have sex with a protagonist and then evaporate (many of which are openly shown to involved in perverse sex acts in contrast to the normal men), or become nagging shrews who contrast sharply with the relaxed male heroes, Despite being a central character in the majority of the seasons, Ari's wife is never given an official name (aside from one throwaway line in late final season episode)* Vanilla Protagonist: It's called "Entourage" for a reason.
You can't help but want to give Lloyd a hug every now and then, considering how much he's suffered as Ari's assistant, who constantly insults him with racist and homophobic remarks. Fortunately, Season 6 has Ari throw him a bone by making him an agent like he wanted.
Dana Gordon in Season 8. She and Ari rekindle their old romance after Ari and his wife separate. Dana falls back in love with Ari and wants to have a child with him even though she's nearly 40 years old. But in the end Ari realizes that he's still in love with his wife and breaks off his relationship with Dana, leaving her heartbroken.
It's the Same, Now It Sucks!: The biggest complaint about the film was that it was essentially a 105 minute long episode of the show with the characters going through their usual plot lines.
They Wasted a Perfectly Good Plot: The series ended with a stinger showing that Ari was being tapped to lead Time Warner, as John Ellis is planning to retire and offers him the job. The opportunities for a man like Ari in charge of one of the world's biggest production studios were endless, but come the time of the movie (which starts immediately after this), Ari is seemingly right back in his old Hollywood agent role and barely gets any time in the new job when he's forced out by the backer of the film Hyde. With the underperformance of the film, any such possibilities of Ari taking on a new job are likely never going to happen.