One thing I didn't really take much notice of was the difference is spelling between English english and US english. I have read so many technology and science books (nearly all published in the USA) that I just accepted the differences.
Until I come to write against a template based on US English where anything ending -ise is flagged as an error 'cos the dictionary thinks it should be -ize. You don't realise how many times you use words like that until somethign like this comes along
The Victorians who introduced using -ise instaed of -ize have a lot to answer for.