Have you ever noticed that nothing good has ever followed the words "no offense" or "now don't take this the wrong way, but..." Usually, what follows is some kind of slight that probably didn't need to be said in the first place...but what do you think the chances are that someone would respond:
"Well, that was pretty rough and probably unfair. But, I think I'll take note of the preceding disclaimer, dust my sleeves off, and just move on."
To my knowledge, that's never happened to anyone, ever.
So a general piece of advice would be to stop yourself anytime you're about to deliver one of these statements and realize that whatever you're about to say is probably going to cause some type of (perhaps justified) offense.
That was pretty obvious, though.
What I think is far less obvious is the way these type of disclaimers take statements that otherwise sound innocuous and add some strange, unwarranted degree of awkwardness and/or, well, offense.
Let me give you an example. I recently met up with a friend in Woburn (how's that for splitting the middle) who was just about to finish up a graduate degree program in Boston. As I understood it then, he was now many tens of thousands in the hole and had no job lined up for afterwards. How do you think these four statements might have come across:
1. So, what are your plans looking like? What are your prospects for after graduation?
2. No offense, but what do you have lined up for afterwards?
3. Don't take this the wrong way, but do you have any post-grad plans?
4. I hope this isn't too personal of a question, but what are you looking at doing after school gets out?
This might already be obvious to you, but to me, Question #1 sounds like one good friend using straightforward, direct speech to ask another to describe what his plans are. That's how I'd interpret it if someone asked me.
Questions #2-4 are all asking the same exact thing and may come from someone with an equally warm heart, but they all come with a subtle verbal jab for the person being asked -- each implies that there's something 'wrong' about the situation. When you stick 'no offense' or some other awkward mutterance before a question you ask someone, you're adding a whole new element to what you're saying -- an implication that there might be offense to be taken.
My advice to readers: Just drop the term 'no offense' and all the members of its family tree away from your vocabulary completely.
Because it a) won't take the edge off an already-offensive statement, and, perhaps more importantly, adds an edge to an otherwise-innocuous statement or inquiry, it serves about as much purpose as a football bat.