A Rant about Spell Check

So I'm sure many of you remember the old poem that was a classic email forward
Eye halve a spelling chequer
It came with my pea sea
It plainly marques four my revue
Miss steaks eye kin knot sea.
Eye strike a key and type a word
And weight four it two say
Weather eye am wrong oar write
It shows me strait a weigh.
As soon as a mist ache is maid
It nose bee fore two long
And eye can put the error rite
Its rare lea ever wrong.
Eye have run this poem threw it
I am shore your pleased two no
Its letter perfect awl the weigh
My chequer tolled me sew.

Well, now I have problems with my spell check.  I'm writing a character bio sheet as the beginning of my novel and one character helps another character find a third character.  And my grammar check part of my spell check decided that it would be better if A helped B fined C.  Which just made me laugh.  And decide that spell checks are complete idiots.
Take another example from my novel, which also likes to re-highlight mistakes, "She's an evil woman intent on taking over the world"  it suggests removing the "an"
Or how about this gem "They have normal names, none of the rest of us do." What does grammar check suggest? Does, instead of do.
Spelling and grammar checks leave me scratching my head in wonder at what other things are mistakes.