I don't call people to task for their spelling or grammar. It seems needlessly nit-picky to me, and irrelevant as long as communication is unimpaired. Besides, in a world of email and texting, it's impossible.
But I do have a couple of pet peeves. There are no such words as "irregardless" nor "orientate". (Ooo, those two piss me off!
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The phrase is "toe the line", not "tow the line". One "makes contact", not "contacts" - it's not a verb, whether Merriam-Webster thinks so or not. And finally, the correct plural of "octopus" is NOT "octopi" - it's a greek word, not latin, and the correct plural of "pus" is equally "poda" or "puses".
It's a shame, I think, that we are losing rigor in language. Besides the loss of appreciation of the wonderfully subtle humor available in poetry and the beauty of a well-stated concept or argument, it leads to a loss of precision in thinking itself - anathema not only to people who specialize in words and literature, but also to technical people like myself, who work in fields requiring the accurate communication of ideas.
Anybody have any I haven't heard of?