If you're a non-sufferer from such tribulations, such as me, you tend to see the glutenophobes, the sworn veggies, the dairy non-tolerators and the vegan brigade in a slightly dim light. It's absolutely not fair, but you can't help yourself. You tend to be looking for their other traits that fit the pattern. They're quite likely allergic to cats and so a visit to your house entails chucking out the moggies and spring-cleaning before they arrive. They suffered terrible asthma as a child, so you have to lay in a special kind of milk. All tea must be peppermint and all coffee decaffeinated. They may well be carrying a bottle of very expensive water, preferably one with a nipple-like contraption that you suck in order to extract the fluid within. Tomatoes are verboten. Blue cheese will poison them. They will almost certainly have a tragic family history filled with trauma and deadly, unusual afflictions. The talk will be about their latest of very many bouts of radical surgery. It goes without saying (though they'll say it anyway) that they have IBS. They are quite likely on the verge of ME, or at least know someone who's got it. They will regale you with the miraculous benefits of arnica and tell you that the amazing NSAID that's the only thing that's kept you alive and moving for the last 25 years is slowly killing you. They will express severe surprise that you haven't wasted hundreds of pounds visiting acupuncturists.

Well not all this rolled up into a single person, of course. And it's not fair. Though I do know this woman in north Devon...