A credit card gets you nowhere.
You can buy cigarettes in vending machines on the street.
You'd better like sausages and potatoes.
Hiking is a favourite Sunday activity.
Paying for a 2€ item with a 100€ note? Sure!
Arrive at your meetings/appointments one minute early.
People offer you slippers when you enter their house.
Grass cutting on Sunday? Think again.
Sweet dishes can be eaten as main courses.
There is no AC.
People carry kids on their bikes.
The pork section at the butcher's and in the supermarket is huge. The other meats are almost non-existent.
Sandals with socks is fine.
Shopping on Sundays? I don't think so.
They open the windows even when it is -10°C outside.
Selling and buying second-hand everything is a national past-time.
When it comes to clothing what matters is not style but rather comfort and practicality.
You can overtake a police car at 220km/h.
Cleanliness is a must.
Cake is always a possibility.
Christmas markets are not to buy things. They are social places, to have a drink and eat a sausage or two.
People carry suitcases on their bikes.
Have a hobby? There is a club for it.
German playgrounds rock.
You will save a lot of money by not being able to pay with a Visa card at Ikea.
Get a plastic cake carrier box if you intend to take one somewhere.
Take your kitchen away with you when you move.
Follow the rules. Always.
Tell anyone off for not following them.
Don't bother with small talk.
Don't cross the road if the little man is red. DON'T.
Riding a bike in high heels and mini-skirt is ok.
Always dress appropriately. Except for the above situation.
Germans will always answer they don't speak English (even if they do).
You can drive as fast as you like on SOME motorways, not all.
And oh boy do they drive fast. Get out of the way!
Hoovering on Sunday? No, no.
People carry Christmas trees on their bikes.
Disclaimer: this is only my experience (a French woman coming from the U.K. living in Germany for 4 years). It does not mean it is universally true. Don't kill me.