The Plane Crash

the boss of a company decided to go on holiday but when he got to the airport he found out that he had forgot his brief case, so he went back to work and got his brief case before he went back to the airport the security guard stopped him and said 'i have had a dream that the plane you are going to get is going to crash'. so the boss believed the security guard and went home and watched the news all night and the plane that he was going to get did crash. the next day he went to work and said to the security guard'thankyou you saved my life the plane did crash' the boss then gave the security guard £100 and said your sacked. why did the security guard get sacked?