Annoying ways people use sources.

Think of when you are reading a source or a book. When reading you are in tune with the book, you read every word and understand every word as well but they would quote someone in something you read. Right there they can add their citation or their quote but depending on how they implement it can alter the flow of the reading. Altering the flow of the reading one, throws off the reader maybe even makes the reader reread what you have said and two, it will confuse the reader and they will not understand where are you coming from with that quote that you had a reason to put it in the reading.

Moral of the discussion having the flow of the reading interrupted can throw off your reading. The reader is reading to understand what they are reading but change that for a second of what's the task they are given you lose them in the reading.