I honestly find it really annoying when people online apologise for their "bad English" without a real reason. I mean, when they're writing a long text and they're really only beginners and the whole thing is almost unreadable, I appreciate your apology. But if the English is quite good and - even if there are some mistakes in it (which most often isn't even the case) - you can understand what they're saying, then I find it annoying. Which freaks me out the most is when the apology is longer than the actual text. I just think that it's not a sincere "sorry guys I know this was hard for you to read", it's more fishing for compliments, hoping everyone will say "noo your English is so good".