Driving on the right
I never got used to the roads in Europe.
I kept looking at cars on the road and thinking no one was driving them, because I looked in the wrong front seat. I kept having that wild moment of panic thinking whoever was driving us around had turned into oncoming traffic. If a group of us were walking down the road and a car came towards us, they'd all head off to the right while I instinctively headed off to the left. In the end I just looked around wildly and constantly when crossing the roads, thinking that a car could spring out at me from any direction.
The only place I didn't have a problem was England, of course. And in England all the street corners have "Look right" painted on them in big writing, for the foreigners. It was the only place I didn't need telling.
It's hard enough keeping one exchange rate in your head, let alone three or four. With each new currency I'd have to write down a bunch of conversions and keep referring to them for the first few days. I'd do things like try and give euros to the shopkeepers in England. I always had to tip all the coins out of my purse and look at them in shops because I couldn't remember which coin was which.
I also took a while to notice they still have one and two cent coins in Europe. In Australia they were phased out fifteen or so years ago. It was only after I bought some fruit and the shopkeeper kept stabbing the docket irritably with a finger that I realised I'd automatically rounded it down and forgotten to give her the extra two cents.
It's very strange being in a train that goes 300k's an hour. But not so strange as being in the front seat of a driverless train. That never stopped freaking me out.
I think it's outrageous that you have to pay for public toilets in Europe. I will never think that's fair. Especially since many cities had free urinals on the side of the street. That's discrimination, people!
The toilets themselves were hard to get used to. German toilets have a sort of shit-shelf. I've had some debate with people as to why - whether it's so you can examine your shit or just so you don't get that leaping drop back up you. The trick with German toilets is to put a wad of toilet paper on the shit-shelf before you start, otherwise it all sticks.
Turkish toilets are worse though. They just have the porcelain foot rests either side of a hole in the ground. The trick with them is to be ready to dash out the door as you pull the chain - otherwise the big whoosh of water gets all over your shoes.