
I would hope that "politely" doing anything is non-offensive by design.
That aside, I typically don't correct anyone's grammar/spelling other than my own. I do make exceptions for "repeat offenders", but I usually do so privately with the intention of sparing them further embarrassment from a continued mistake.
Ultimately, I don't expect anything even nearing perfection, and I only really care if the mistakes are making things unclear. For example:
"this weekend i helped my uncle jack off a chocobo"
^ I'd request clarification on that really, really fast.
That aside, I typically don't correct anyone's grammar/spelling other than my own. I do make exceptions for "repeat offenders", but I usually do so privately with the intention of sparing them further embarrassment from a continued mistake.
Ultimately, I don't expect anything even nearing perfection, and I only really care if the mistakes are making things unclear. For example:
"this weekend i helped my uncle jack off a chocobo"
^ I'd request clarification on that really, really fast.