the use of square brackets surrounding any word or phrase indicates an understood expletive before the bracketed word or phrase and emphasizes strong feelings on a subject. The reader then has the option of inserting the expletive at their discretion.
For instance, work
could be read as "fuck work."
Note: Brackets can also be used when speaking by using hand gestures. While using the word you wish to bracket, simply put your hands up with your thumb and middle finger forming the shape of the square brackets.