There is a huge difference if english is your first or second language. If it's the latter, you'll still have some features of your first language in it (not just accent, but also about the way you form sentences and the cultural background). Thats why you can usually say if someone is a native speaker or not.

And since i believe you are german, at least in my english/german bubble we use war more casually. But that is just my experience, not fact.