When someone makes a big deal of showing off his or her knowledge or is too concerned with literal accuracy or formality, that person can be referred to as pedantic. Often pedantic people show off their knowledge by correcting small errors that do not matter in the grand scheme of things. This can be annoying to those around them.
Below are some examples of pedantic.
Now you have lots of different examples of people being pedantic, even when it frustrated those around them.