I used to work in a call centre for Motorola phones. We used to repeatedly get morons phoning us on their faulty mobiles, in order to prove what the problem was. A classic was the guy who couldn't hear what the other person was saying. So as I was trying to initiate the conversation ("Hello? hello? Is someone there?") he was shouting "You see? I can't hear you!"
One guy phoned up to moan that his mobile phone didn't have a calculator on it. His friend had bought a Nokia, and his had a calculator. I told the caller that he should have bought a Nokia then.
Me - what type of phone is it?
Caller - I don't know.
Me - well, is anything written on the phone?
Caller - Samsung.
Me - yes. You are of course aware that you are calling Motorola.
Caller - oh. (one guy even said "well, all mobiles are the same, aren't they?)
Then there are the ones who call you to arrange a repair, and when you ask them (without realising that they're on their mobile) to remove the battery on the mobile and give you the serial number, the line goes dead. I can just imagine them taking the battery out and then holding the phone back up to their ear and trying to continue the conversation.
I always say that, instead of just going into a shop and buying a mobile, you should be allocated one according to your IQ.