I'd appreciate some feedback on an answer I just posted. If I've gone overboard with the sarcasm, please advise asap.
"Common sense" may be an easily abused and subjective term, but (is this a bit sarcastic?): Use your common sense.
Stack Exchange in general doesn't permit profanity or abusive language. This is pretty much the only reason I can recall I or any of the other moderators here taking significant action (yes, we can suspend your account) with regard to communication standards.
Generally we expect you to express yourself in a manner that might be appropriate to a work or school scenario. Of course, not all such things are created equal.
Silliness is okay, within reason, i.e., reasonable silliness. Being nice is also acceptable.
Written communication lacks a lot of context we take for granted when we speak to people face to face; one of the problems this presents is that there is probably a wider range of potential interpretation. While I don't think you are responsible for someone taking directness or curtness for meanness, it is something you might want to keep in the back of your mind. If someone flat out accuses you of such, don't escalate the situation but simply say this was not your intention and you are sorry if any feelings were hurt, etc.
If you thought your post was in any way risqué, I think you have nothing to worry about.