I was watching some show where the questioner prefaced his statement with the phrase "with all due respect," and then slammed the guy. I have never heard this phrase preface a statement that evinced any respect. I don’t see why people say it, because it’s such a cliché it doesn’t palliate anymore. There are words, called autoantonyms, that mean both themselves and their opposite, such as moot, which can mean debatable or irrelevant (others include: literally, weather, fine, fast). But then there are phrases that only mean their opposite. Here’s a list, perhaps you have others:

• I don't want to tell you what to do – I love telling you what to do
• Of course it's none of my business, but – It should be my business
• I hate to say this – I love saying this
• This won’t hurt a bit – this will hurt a lot
• It’s not about the money – it’s about the money
• it’s not you, it’s me – it’s you
• I don't mean to be rude, but or No offense, but or Don't take this the wrong way, but - what I’m going to say is rude and offensive and can only be taken this way
• I could care less - I couldn’t care less
• Heads up!- Duck!
• This is just my opinion – but it's God's truth, too
• The fact is or History proves – I will assert without any empirical support
• I didn’t say he was a (racist, anti-semite, liar), but – It is clearly implied
• I’m against Saddam, but or I’m against Castro, but… they are small beans compared to Bushchimphitler