'My wife hates spiders. I learnt long ago that a shriek from another room didn’t mean that a maniac with an axe had broken in, but that a half-inch spider had just careered across the carpet. An ability to tackle spiders has given me a touch of hero status in her eyes, as if I had seen off a gang of feral hooligans single-handed. There is no logic to phobias....I bet there’s something illogical that petrifies you...' writes our regular columnist Professor David Haslam.