My spell checker makes some incredibly non-sensical substitutions, such that I cannot follow the logic in the changes. I think the spell checker is a product of your search system. I have FireFox, mainly because it does less information harvesting (and it is free and seems competent. The spell checker, less so.)
When I started using word processing, I was convinced that the spell checker would make ma a “lazy speller”. But instead, it trained me to correctly spell many of my troublesome words. At this point, I do much better without a spell checker than with one.