If this is an ongoing process, one could extend it to the future; i.e., if you're writing a story set some decades from now, you could have some phrase currently found unambiguously offensive used in an innocuous way in the dialogue (i.e., in 2030, something like "go bugger yourself" will mean "really?". For extra points, make the phrase colourful and/or anatomically implausible.)
I meant "you like Gazza" in the first instance.
Reminds me of one nuance of our own idiom, where saying "Gazza is a bastard!" means you Gazza, whereas saying "Gazza is a bit of a bastard" means you detest Gazza.