I stood on the supermarket forecourt gawping for a good twenty seconds after the stranger strode over to the bicycle, booted it to the ground, lifted his bike over it and cycled off with his rust covered jacket flapping in the wind.
He hadn't heard my friendly quip and seemed utterly enraged that someone had blocked him in.
It was the second time that day that I saw a German get annoyed by rule breaking. The first time was just a few moments before.
"I'm sorry, I've had it for a long time and I kept forgetting," I stammered to the supermarket cashier, as I attempted to iron out the piece of paper.
She raised an eyebrow as I handed her a faded crumpled receipt for the empty beer bottles I'd returned to the machine over 3 months ago.
In Germany, the shops pay you to recycle. But there's a system. You return the bottle to a machine, take a receipt and collect your money at the cash desk before you leave. I hadn't done that. I'd returned to the supermarket over and over, and each time I got to the cash desk, I'd forgotten to surrender the receipt. Through my forgetfulness, I had broken the rules.
"It may not work," I said, nervously trying to pre-empt her rage.
The bar code on the scrunched up paper didn't work, and the woman’s frizzy greying hair seemed electrified with annoyance. She raised another eyebrow as she stabbed the reference number into her keypad. Maybe she was irritated because I was costing her time. Maybe she was incensed that for 3 months, two weeks and four days, I had forgotten over and over again to do this. Or maybe it was my nervous apologetic tone that she couldn't handle. After all, wouldn’t a German be more mater-of-fact about this?
The pensioner who had gone before me snatched his last jar of pickled gherkins and muttered something under his breath. Either he too was fired up about the non-conformity of my receipts or he was relieved that I'd given him enough time to bag all his shopping before the cashier started racing my groceries over the bar-code scanner.
As I left the supermarket, I walked into another uniquely German uncomfortable situation.
I fully admit I'd realised when I chose the parking spot for my bike that it might be controversial. It had been an opportunistic decision - I'd seen a space beside the stack of carbonated water bottles and gone for it. As I parked it, my hairs stood to attention and I almost expected a comment from someone nearby about what a thoughtless place it was to park my bike.
But no-one decided to get involved in my business that day.
On my return to the scene, I notice a middle-aged man had parked his heavy Dutch bike even further into the supermarket's pavement displays of special offers.
I was relieved, and decided to offer up some jovial camaraderie.
"It looks like there's a bit of a traffic jam here at the moment," I said with a smile, gesturing at the bikes on the curb which were blocking us both in.
Before he could reply, I watched in slow motion as he forced the offending bike to the ground, lifted his bike over it and cycled off without a word.
I stood for a few moments in utter disbelief. It was only later that my boyfriend Daniel explained this mysteriously violent behaviour.
"Germans don't like it when people break the rules or when they disrupt the order."
This same fear of chaos and desire for order is what drives Germans to buy a train ticket, even though there are no ticket barriers to check up on them. It's what stops Germans from crossing the road on a red light, even when there are no cars.
Instinctively this characteristic feels sinisterly militaristic and I wonder whether it dates back to a Prussian addiction to rule making. But perhaps it's what also allows Germans to have a transport system that's based on trust. One thing’s for sure though, it's non-negotiable: Ordnung muss sein.
