On Gullibility

I like practical jokes. The problem is I like a practical joke to be advanced, really suckering in the poor victim before they realise they've been "had." Recently I had someone in my car, and I told them that I had voice activated windows. I told him to say "window down," and imagine his surprise when he did the window started to open. I said to say "window up" and again, it followed his command. He then spotted me opening and closing his window from my side of the car. The fact that he'd been told what to say by me, and the window ignored me, only listening to him, should have told him that perhaps he was being led on.
One of the greatest practical jokes I have ever played was on my boss when I was working in the arcade on Southend seafront. It was his birthday, and that morning I had popped down to the shop to pick up tea, coffee, sugar and milk. On the way back up the seafront, I spotted his car being driven away by someone else, and a little devil appeared on my shoulder.
"Where's Danny's car going?" I asked a collegue.
"His wife's treated it to a full valet," came the reply.
I popped into the arcade next door, where my mate Paul was working. I asked him if he knew anyone who could help me with a practical joke, and he pointed me to another seafront worker who is apparently notorious for being able to wind people up without laughing. I went and had a chat, and the plan was to pretend he was the Police, saying that the car had been involved in an accident at a road just around the corner from where I'd seen it. The driver had been seen running from the scene, and could Danny account for his whereabouts.
The call came about an hour later. Danny was in the office, with the big boss. He came out, stern and serious look on his face and said "my car's been in an accident."
"Really?" I enquired, "What's happened?"
"It's been smashed up around the corner, and the driver legged it."
"Oooh, that's terrible," I reply.
"The Police will be coming to see me later, they need to take a statement."
It was at this moment my granite expression broke. I smirked, only briefly, but Danny caught wind of it.
"IT WAS YOU, YOU BASTARD!" he shouted at me.
Apparently after the call from the Police, he'd phoned the place doing the valet.
"You bastards. You smashed up my car!" he yelled down the phone.
"No we didn't" replied the garage, "I can see the car in front of me."
"Eh? Wha? Erm..." *pause for thought processes to complete* "I've been had."
He then hung up.
I've never made a practical joke of that quality since.