[piaste]

It's even worse. People are exceptionally good at rationalising whatever it is they want to do and turn them into convenient rules that sound noble and high-minded.

It would be a much less frustrating world if the robber who takes your money would just tell you "hi, I'm taking your money because I can and because I like it" instead of earnestly believing that he deserves it for some complicated reason (pick your example).

[AndrewDucker]

Oh yes, retroactive justification is mostly what people do. And aren't aware that they're doing it most of the time.

Most muggers don't try to justify themselves philosophically, thankfully. That would just make the experience even more painful.