The right man for the job

A few weeks back, I was shopping with a friend late at night when my phone rang.
It was my P.G. student from the college where I teach. 
Since it was late, I wondered what was up when I picked up the phone.
Me : Hi, A.
A : Sir, are you busy ?
Me : No problem, man. Tell me.
A : I needed some help, sir, and I figured you're the best person to ask.

My chest swelled up with pride. Sure, I was the youngest of the staff in my department, but apparently, the students had already seen some spark of genius in me. In a department filled with professors and associate professors and people with 30 odd years of experience, they obviously felt I was the most knowledgable in patient management. That's why even late at night, when the poor kid had a doubt while studying, he immediately called me.
I mentally prepared myself for tough questions on neuroanaesthesia, drugs and side effects, complex formulae and classifications.

Me : Of course. What's your doubt, man ?
A : Sir...
Me : Yes...
A : My Facebook homepage has changed. Can you tell me where the 'Sign out' button is ?
Me (and my ego) : .....