The funny spelling of centre always gets me too, it just looks so wrong! I can get used to writing words that end in ise as ize, and colour as color. But center, fiber, liter, etc just don't sit right.
It's just a matter of getting used to. I imagine these spellings do not evoke the same feeling in you, even though they are objectively following the same rule as centre and fibre:
Centre look and sounds like “cent-ruh” rather than the rolled out sounding of err sound to make “center”. Then again, how you say it is a bit different, too.
Maple not Mapel
Cable not Cabel