Sometimes I worry about myself. Only sometimes.
The other morning, it was just before 7am and I found myself in the changing room at a health club. It wasn't the fact that I was at there at such a stupid hour of the day which worried me, it was what happened next.
I was standing in the third bay of lockers, with the higher numbers, and I happened to be standing in front of locker 193. And then it occurred to me that I am usually at the lockers with lower numbers, and instinctively I always use a locker which is a prime number. This is easy when you're standing near the first 20 lockers, but in that second, rational thought deserted me, and I realised that I could only use the locker if 193 was prime.
So there I was, standing with a pound coin in my hand trying to work out at 6.50am whether 193 is prime. It didn't take me long to work out that it is prime, and I made it into my session on time for a 7am start. I knew you'd be pleased.
Now - just to be clear - there may be those who think I have made up this story for comic effect. I offer two objections to that notional. Firstly, I assert that the story is absolutely true. Secondly, I assert that there is no comic effect present at all.