Developers who are new to a language or a platform are usually greeted by encoding issues. One example is beginner PHP/MySQL developers. They usually create a simple form page, post some data with it, persist that data with on the back-end, refresh the page, and realize that all unicode characters are gone and in their place, there are some weird, incomprehensible characters.
I’ve recently encountered a similar problem in one of my projects, namely, a desktop application written in C# running on Mono. When run on OS X, my app began acting strangely, and when I looked at the logs, I realized that all umlauts/diacritics/accents on my characters were next to the base characters, rather than on top or bottom. Here’s an example: