[mikael]

In the UK, and other countries where the English spelling patterns follow the UK tradition, what you call "center" is properly spelled "centre." There are other terms which have different spellings as well, such as favour, honour, colour, etc.

To insist that only your preferred spelling form is appropriate and/or "correct" is rather arrogant, don't you think?

The purpose of language is supposed to be communication, not dominance.