Usually, when I programme for myself or in a German-only team and they agree, I/we do it in German because it makes naming things much simpler (no naming conflicts, never, and a strict visible separation between your code and libraries).
This time, I thought: "Nooo, let's do it in English, because, you know, reasons and it fits into the situation"...
Booom, stack overflow!
"How in the hell did that happen?" I never had a stack overflow before outside of recursive programming.
And what was it? I had made a class to encapsulate an API, added a property with getter and setter, naming in English and similar to the said API... very similar... in fact, the property had the same name as the API function, resulting in a getter calling itself over and over again.

This was a harmless mistake, and found very quickly, but it's interesting so see how a habit (or working method) probably prevented similar or worse sources of error in the past.