Seriously, I’ve never not ignored spell checkers. Some obvious deficiencies occur (with almost any nationality of checker) when two spellings can be used with different meanings. E.g. a dialog box vs a dialogue between people.

And if you think spellchecking is annoying, you should try using a US keyboard. For a while I used one, but kept the UK keymap. Trouble is that UK keyboards have an extra key (backslash, between left shift and Z, is missing on a US one) so I couldn’t actually type backslash on my UK-but-really-US keyboard. Or vertical bar. Well, not without resorting to Alt + numpad antics. These days, I use a nice reconditioned Model M with a UK layout.