Today I got a phone call that helped me realize one thing that Linux can't do, at least not yet:
"Hello Sir, I am calling from [unintelligable speech], to help improve the performance of your computer."
"Ok."
"I will tell you how to do this. The first thing you need to do is turn your computer on."
"It is already on."
"Then I will have you click on Start."
"I don't have a Start button."
"... You have a Macintosh?"
"No, I have Linux."
"Excuse me?"
"I have Linux."
"You have a Linux?"
"Yes."
"I am sorry sir, we only provide technical support for Windows computers. Goodbye."
