Words like Theatre, colour, glamour, and catalogue are all spellings that I was taught to use and that just feel right for me, whereas realise does not feel like me. I will never write catalog. I would not be comfortable writing anything formal using that spelling as it just FEELS more casual to me. And regardless of what your dictionary will tell you, every little bit of every word means something. Visually words have a different affect, just as they do depending on pronunciation, and syntax. In writing, everything is (or should be) a deliberate choice, and a specific one. Every detail counts. I am a word-freak, and a poet, and every one of my choices makes an impact on my writing. It has nothing to do with pretentiousness.
"We don't value the lily less for not being made of flint and built to last. Life's bounty is in it's flow, later is too late. Where is the song when it's been sung, the dance when it's been danced? It's only we humans who want to own the future too."
- Tom Stoppard, Shipwreck