"What's the point of this operating system?"
Say you and your wife decide to have another baby. After a lot of hard work, she gets pregnant. After nine difficult months and the troubles of childbirth, you bring a new beautiful little person into this world. You could not be happier. This is the best moment of your life.
Then imagine me walking in, and saying: "What's the point in yet another human being?"
Other annoying quotes are at the original site: http://www.osnews.com/story/21944/The_10_Most_Annoying_Things_in_Internet_Comments