SPOILER WARNING: This article contains major spoilers for Ant-Man and the Wasp, in theaters now.
The Marvel Cinematic Universe's S.H.I.E.L.D. may be on the side of the angels, but their tactics aren't necessarily. While Agents of S.H.I.E.L.D. presents a highly proficient spy organization, the S.H.I.E.L.D. of the films can range from incompetent to annoying to downright insidious. Ant-Man and the Wasp continues this trend with the introduction of Ghost and former S.H.I.E.L.D. agent Jimmy Woo, who -- due to post-Captain America: Civil War circumstances -- hinders rather than helps our heroes. For the purposes of this article, we'll only be looking at S.H.I.E.L.D. as it appears in the films, but not on television.
S.H.I.E.L.D.'s cinematic tenure began in the first Iron Man film, which also launched the MCU. While later films would reveal the organization's storied history, S.H.I.E.L.D. -- much like Stark himself -- appeared to be finding its feet in this film. In a series of sequences that now appear to be tongue-in-cheek, Agent Phil Coulson himself didn't even have the acronym straight quite yet, as he referred to S.H.I.E.L.D. by its full title: the Strategic Homeland Intervention, Enforcement and Logistics Division. Hapless but insistent, he made several attempts to arrange a meeting with Tony Stark, only to be shut down by Pepper Potts.
Of course, Coulson and his small team of agents got a little piece of the action in the film's climax. When Pepper realized Obadiah Stane's plan, she called Coulson and he turned up at Stane's lab with his team. By that point, though, it was too late; Stane had already suited up as Iron Monger. The agents tried to defend Pepper (and themselves), but Stane tore through them like tissue paper. It is unclear how many survived the quick battle, though Coulson obviously went on to appear in Iron Man 2. This was the last time S.H.I.E.L.D. appeared in the film -- and they were hardly any help at all. Fortunately, Stark went on to stop Iron Monger and save the day.
In Iron Man 2, S.H.I.E.L.D. was a spot more helpful. The organization sent Natasha Romanoff undercover at Stark Industries, and -- fortunately for Tony -- she made a discovery that pulled him back from the brink of death. When she realized his arc reactor was poisoning him, she reported her findings to S.H.I.E.L.D., who developed a cure for his symptoms (but not the poisoning itself). With some help from Coulson and Natasha, Director Nick Fury was able to pin Tony down long enough for the shellhead to come up with a solution for the poisoning. Cured of his ailment, Tony went on to defeat Anton "Whiplash" Vanko and save hundreds of innocent lives. Even after all that, though, Stark didn't exactly get a glowing assessment and the Avengers Initiative seemed to pass over him, despite S.H.I.E.L.D.'s desire to keep him on as a consultant.
S.H.I.E.L.D. was slightly more antagonistic in Thor, where Fury sent Coulson to investigate Mjolnir's crash landing in New Mexico. For one, Coulson pulled a major dick move and confiscated astrophysicist Jane Foster's research from the night Thor was beamed down to Earth. In spite of their good intentions, S.H.I.E.L.D. also attempted to prevent Thor from reaching his hammer and then detained him. Though Coulson ultimately released Thor, he remained suspicious enough to have a few agents follow the God of Thunder around. This led S.H.I.E.L.D. to be present at Thor's grand reveal, which in turn inspired Coulson to give Jane her research back -- as well as access to S.H.I.E.L.D.'s satellites, as a little something for her trouble.