It is interesting what triggers memories, even those which have been buried in the deep, dark pit of your mind for decades. Anything can trigger them: a sound, a smell, a sight, or even as little as a few pixels, generated with recycled electrons that landed in your email inbox.
The latter happened this morning, and so it is that I suddenly find myself back decades ago. But am generous and like to share, so I'll take you on my journey back. Imagine the following: It is a warm summer day in 1960s' Germany. You are a small child, visiting relatives in a rural area.

You open the back door of the house and start running over the yard. The moment the smell reaches you, you slow down. The little hut has a wooden door with some sort of knob, only that it isn't a proper doorknob but just a rectangular piece of wood which you turn to open said door. You take a deep breath and stare inside. It is sombre in there, and unlike anything you've seen before. But what is it you see? It's a plank with a hole in it. You enter and lock the door behind you by putting the hook in the eye. Don't look into the hole, it's ghastly what you'll see there (I know, because I peeked into that hole). You have to be quick, and to fight your urge to vomit. The need that brought you here is too strong, you have to cope with the situation. In your hurry, you fumble with your clothes, losing precious time. You try to be fast, the air in your lungs won't last forever, and then you'll have to breathe again...

You find that you can't just hover above that hole – the plank is too high, or you are too small. You have to sit down, putting your hands on the plank for balance! Uggh! Try to avoid the liquids splashing up touching your skin. You are close to retching. You have to breathe, but you successfully fight that urge to vomit. You'd never be able to stop vomiting again, because you'd have to turn round and actually face that hole, bringing your nose and mouth close to it. This would be even worse than doing what you've come here for in the first place. Eventually, after what seems like ages but was in fact only a few minutes, you can turn your back on that horrid place and firmly close the door from the outside. And as you're at it, you firmly close the door to that memory, too. Until the day when somebody accidentally opens it and releases all the bad smells.

Golden childhood memories? Even now, some 40 years later, remembering it makes me sick in the stomach. It's all there again, the feeling of disgust, the smell – just not where it was. I wonder whether my sensitivity to toilet smells was caused by this experience.

Allegedly, Martin Luther¹, who suffered from constipation, considered his digestion problems (which kept him stuck on the toilet seat for hours) to be the work of the devil. I am not surprised.