Blonde Goes into Store

A blonde goes into a nearby store and asks a clerk if she can buy the TV in the corner.

The clerk looks at her and says that he doesn't serve blondes, so she goes back home and dyes her hair black.
The next day she returns to the store and asks the same thing, and again, the clerk said he doesn't serve blondes.
Frustrated, the blonde goes home and dyes her hair yet again, to a shade of red.
Sure that a clerk would sell her the TV this time, she returns and asks a different clerk this time.
To her astonishment, this clerk also says that she doesn't serve blondes.
The blonde asks the clerk, "How in the world do you know I am a blonde?"
The clerk looks at her disgustedly and says,"That's not a TV -- it's a microwave!"