When this quote is said the speaker acts as a complete douchebag and make the person you are talking to feel like a complete dumbass. Can be said even when the subject is NOT common knowledge.
Student (on exam): "Teacher, we never learned how to find the graph of a logarithmic equation."
Teacher: "Well, it's common sense really."
Student (thinking): douchebag
Teacher: "Well, it's common sense really."
Student (thinking): douchebag
by () February 07, 2010