Smegma, stale urine, the caseous discharge from sebaceous cysts, steatorrhoea, purulent phlegm, I've many times been on close and uncomfortably intimate terms with them all, even endured the occasional explosive spattering.
But one day I crossed a particularly repulsive Rubicon, when Joe belched pungently right in my face, having obviously just eaten a curry that included ghost chillies, garlic and onions (as an Epicurean, I thought I could also detect a little note of vanilla), and ever since, I've been a bit leery of physical examination.
So when Sir William Osler advised: 'Listen to the patient and they will tell you the diagnosis,' that was all right with me. It also sounded pretty good advice on my very first day on the wards as a happy and horny medical student, when I asked my first patient what was wrong with her.
'Systemic lupus erythematosus,' she said; boy, I thought, this diagnosis thing is a piece of cake. But that was a one-off, never to be replicated, so gotta tell you, Sir William, the truth is that patients will not tell you the diagnosis.
It's easier in hospital. You are surrounded by colleagues who can offer advice and a handy second opinion (OK, most of them are hoping you will trip up and make a fool of yourself, enabling them to leapfrog you on their way up the slimy ladder of career advancement) and there are machines all around with bells and whistles attached, which may not be doing very much but always seem to reassure the patients.
But out on the mean streets of general practice, it's a different story. Diagnosis is not a straight road, but full of little eddies and meanders, red herrings and cul-de-sacs. And deception; to quote Granny Weatherwax: 'Things that try to look like things often do look more like things than things.'
I always say, if you're looking for a needle in a haystack, the last thing you need is more hay.
- Dr Farrell is a GP from County Armagh. Follow him on Twitter @drlfarrell.