Mikey, you write, "I can't be asked." I have never understood why anyone would say this rather than the more obviously correct, "I can't be ar$ed."
Saying, 'I can't be asked' is absurd; absolutely anyone can be asked absolutely anything, surely?
On the other hand, the 'ar$ed' version is probablt derived from earlier sayings such as, "I needed his help but he didn't bother his Yabbie." That may, in turn, have come from a more impolite request such as, "Get off your Yabbie and help me with this."
The notion, of course, is that the rear end is central to whatever activity might be involved...and I don't mean that rudely!