A reaction gif of a female recruit / soldier turning her head and proudly announcing "I'm doing my part." This is from 1997 sci-fi movie Starship Troopers.
A funny reaction gif of a bearded man listening to music through his headphones and nonchalantly nodding his head; all before he casually puts a gun to his head. This is from an old Christian documentary called "Is Rock Music Evil?"
A reaction gif of a bird staring rather excitedly while the text "...Friend?" appears. Obviously, this can be used whenever it seems as though you've just made a new friend.
A reaction gif of a small kid dancing at an NBA game. After realizing that the camera has zoomed in on him, he takes off his sunglasses and points at the camera. This is from an Indiana Pacers game.
A reaction gif of Leonardo DiCaprio shouting "Get off the phone!" This is from The Wolf of Wall Street (2013), in which he portrayed a rich stockbroker called Jordan Belfort. In this scene, him an Jonah Hill (Donnie Azoff) were high on drugs. I saw this one with the caption: "My reaction when I'm trying to tell my friend a story and he gets a text."
A reaction gif of jazz instructor Terence Fletcher shouting "Not my f*cking tempo!" This is from the movie Whiplash (2014). The character was portrayed by actor J. K. Simmons (previously played Vernon Schillinger on the TV show OZ and Dr. Emil Skoda on Law and Order).
A reaction gif of English actor Simon Pegg saying "I'm not proud of it" before quickly following up with "I am a bit." Source: The World's End (2013). Character: Gary King.
A reaction gif of Leonardo DiCaprio looking confused before saying "What the f*ck are you talking about?" This is from the movie The Wolf of Wall Street, in which DiCaprio played stockbroker Jordan Belfort.
A reaction gif of GOB (George Oscar Bluth) staring off into the distance as the lyrics "Hello darkness my old friend" play in the background (the song is called The Sound of Silence by Simon & Garfunkel). GOB is a character in the television series Arrested Development.
A reaction gif Kevin Spacey saying "Because I was afraid, OK?" This is from the 1995 film The Usual Suspects, in which Spacey played Roger 'Verbal' Kint.
A gif of Benedict Cumberbatch drinking a cup of tea while the caption "Drinks Tea Angrily" appears. This is from the TV series Parade's End, in which Cumberbatch portrays the character Christopher Tietjens.
A weird-but-funny gif of some sort of exorcist goat twisting its head. Sometimes, this is used as a reaction gif whenever a person overhears somebody talking about them.
A gif of a grey-haired man laughing at a conversation between two men as he is standing at a filing cabinet in the background. This is typically used as a reaction gif / visual metaphor for somebody that is trying to inject themselves into a conversation that they have been listening in on. Apparently, this is from a hearing aid commercial.
A reaction gif of KTLA anchor Chris Schauble looking around in shock. This is from St. Patrick's Day in 2014, when Schauble was reacting to a 4.4-magnitude earthquake.
A reaction gif of John Candy saying "Okay. I see." This is from the comedy film Planes, Trains and Automobiles (1987), in which Candy played the character Del Griffith.