Been watching a Netflix series called "Hollywood Masters" where actors & directors are interviewed in front of acting classes at Loyola Marymount. I particularly enjoyed the one with Amy Adams, who it turns out has done SEVERAL movies I'd never heard of.
Case in point, Doubt (2008) with Adams, Phillip Seymour Hoffman and Meryl Streep. Hoffman plays a priest who may, or may not, be having an inappropriate relationship with an altar boy. Streep plays the Mother Superior accuser, Adams the novice nun who takes his side.
Now, even realizing that Catholicism drives me crazy, still the movie was really well done and very unpredictable. Streep and Hoffman play their roles with fire and fury, and Adams realized early in the production that her role was to be small, and meek, and withdrawing, while these titans of acting ate up the scenery.
It's a master class in submersing yourself in a role.