We Don't Do That Here
“We Don't Do That Here” is a meme referencing a quote from the 2018 superhero film Avengers: Infinity War.
The line in question originates from a scene near the middle of the film in which the character of Bruce Banner (Mark Ruffalo) attempts to show respect to King T'Challa (Chadwick Boseman) by bowing, only for T'Challa to tell him, "We don't do that here."
As a meme, a collection of gifs from the scene in question was posted to Tumblr on April 27th, 2018. A few weeks later, an isolated image of the final gif with the iconic line subtitled was used by another user. After that, the popularity of the line as a reaction began to grow from there, jumping to other websites like Twitter and Reddit in the process.
The line, "We don't do that here," is meant to be used in a similar way as in the film it was taken from, i.e. correcting someone's assumption about a tradition or etiquette within one's culture or community. This is often taken to humorous effect like in the original usage of the image as a meme, wherein the user compared a hypothetical stranger's organized method of planning a writing project to their presumably haphazard style by saying that they "don't do that here."
Additionally, certain users have taken to editing the original screenshot in ways like blacking out different letters in the original quote. This allows the image to be adapted to different situations while retaining a generally similar tone of correcting or instructing others about something they should not be doing. One example of this would be an image captioned, "When you walk passed the janitor mopping the floor," with the quote edited to read, "Wet here."