Spelling and grammatical errors almost always bother me, although it often depends on how much I like the person making the error.
I think the one that bothers me the most is "wrecking havoc." After all, why would anybody want to wreck all this nice havoc? 
Language certainly does change and needs to be flexible though; I've certainly played fast and loose with it enough times. I think one example of what you're saying would be the odd ways that people have been using the word "anymore" for the last few years; nothing grammatically wrong with it, it's just kind of weird.


No, there are definitely mistakes-- and general low standards-- when it comes to spelling and grammar. Words have correct spellings, so to not use them is wrong. Phrases that are contradictory or nonsensical or grammatically unsupportable-- like "could of" or "could care less" or "wrecking havoc"-- are wrong. Some aren't necessarily grammatically wrong, but lack a certain logical accuracy-- liked "based off" instead of "based on."Have any of these topics complaining about grammar or spelling ever worked out? Either it's an acceptable alternate spelling from another country, or the people claiming to be experts wind up disagreeing, with both sides having legitimate arguments. I've yet to see one of these topics come to a definitive conclusion on anything.
Maybe people need to not be so rigid when it comes to language and realize it's a constantly changing thing.
Language certainly does change and needs to be flexible though; I've certainly played fast and loose with it enough times. I think one example of what you're saying would be the odd ways that people have been using the word "anymore" for the last few years; nothing grammatically wrong with it, it's just kind of weird.