"I'm doing the best that I can!" and other such lies I've been told...

At what point should I start getting offended that I am thought to be such a flaming moron that I would buy these out and out lies? Some of my favorites are great, like, "I'm doing the best that I can!" or "I did NOT do that!" or " I did NOT say that!" when there is evidence to the contrary to these statements. How about those classic greats like, "That's NOT what I meant!" or "That's not what I said!" How about, "It's not MY fault!" or "I have NO IDEA what you're talking about!"
These days I just listen and nod my head. It's no use trying to argue with an idiot who thinks they are getting away with whatever it is they're saying while finger pointing and changing the subject all together. Then I laugh about it all later with friends, who find it as amusing as I do. I laugh about all manner of things these days and it feels good. I laugh over frustrations and sorrows and on some level, it makes me feel a little better. I'm still working on stuff. Laughter just helps make things easier.