Why do they laugh so?

It happens occasionally, usually on the phone becasue people are ruder anonymously. Funny how that works. It's the ole George Carlin asshole equation. The farther away a person is physically the bigger an asshole he is. Today I was trying to clarify a question from a patron because she asked a simple question in a convoluted manner and I just wanted to be sure to answer her question correctly. In order to be sure I was looking for the correct information I stated her question in a simpler and more straight forward way. After I did that she laughed at me and said sarcastically, "Uh, yeah."