Watch Heather as she puts out the chairs for the staff meeting - they all have to be touching and lined up with the carpet - and see Mary, who can't pass a wonky picture without straightening it. There's Alan, who can remember all Nottingham Forest's results since 1965 but can't remember names, and Jeff, who is a great art teacher but the parents don't quite get him... and he certainly doesn't get them. As for myself, I'm rarely without a blob of Blu-Tack or a paper clip to fiddle with. And my aunty takes things so literally she screeches to a near halt every time she sees a "Slow" sign in the road.
I'm referring to aspects of autism. It is called autistic spectrum disorder for a reason. Most of us are on the spectrum somewhere, whether we're hovering around red with a pair of lucky knickers or cruising in violet with a need to fiddle with car keys.
The truly autistic, I suppose, are marooned in the sea green that is the middle of the spectrum. They have problems with communicating, are anxious and afraid, and find social contact and the world in general perplexing.
Autistic people are sometimes seen as "other", yet the difference between "us" and "them" may only be a matter of degree. We all exhibit symptoms of the condition, whether it's a particular routine for hanging up the washing, a mania for collecting and sorting beer mats, or uneasiness if our schedule changes.
Autistic people are supposed to be in their own little worlds, believing everything around them is just for them and that people can read their minds. How like us all. A driver has only to be travelling at a couple of miles an hour above or below what I consider to be correct for me to write them off as speed freaks or slowcoaches.And I expect that everyone in the post office queue should realise that it's my lunch break and I get furious when people take what I deem to be too long.
As for theory of mind - the knowledge that other people have their own thoughts in their own heads as valid as our own - we kid ourselves if we think that ours are fully developed. We don't really believe that people starving in Africa can be hurting as much as we would be if we had no food, or that people bereaved through war, on the other side of the world, feel the loss as deeply as we would.
I wonder if autism is an extreme version of common experience and is perhaps a sort of survival mechanism. After all, if we truly could read people's minds it might not be bearable. And order and routine can make for a more harmonious life. Hang on, I'm just looking up at my shelves and someone's returned a book without putting it back in alphabetical order...
Maria Corby is deputy head of a special school for pupils with severe and multiple learning difficulties. She writes under a pseudonym