Example #1: The Window project.
I arrived to Copenhagen for the first time last night at 1am. I rented a nice place for my stay during the next two following weeks. The first challenge that I encountered was trying to figure out how to close the windows in the place that I rented. I have instructions of how to use almost everything around, but I guess the owner is to familiar with the way things work around him that he did not think this will be an interaction challenge for me. It took me 5min to figure the problem.
Example #2: The plug
I find challenging to figure out which adapter to use in each country. The part that took the longest to figure out is that in Copenhagen once you plug the device there is a switch to provide power to the outlet, a 2 way step process that could easily be evolved into a one step interaction. Standard electrical plugs around the world will help us a lot!
Example # 3: The Mailbox
I interact often with this digital interface, so far I found it one of the most efficient ways to deal with an old interaction method.