Honestly, I consider myself a rational person who chooses their battles sparingly and wisely, and I expect much more of myself than those around me. I expect to be respected, but I don't think I excessively nag and ask for things "just because I said so."
The only recent nagging that I can think of involved my dad and I. My dad decided to purchase a newer-model SUV for my little sister who just got her license. Now, I'm the oldest of 4, and my brothers and I all got pieces of junk for our first cars. Clearly, my little sis is favored in every way by my father (there's more stories)...the kid gets everything she wants (and FTR, she can't even drive well)! I nagged him that he was being unfair and showing clear preference toward my sister above everyone else despite the fact that she does nothing spectacular. My dad simply responded, "You know life's not fair, and it's my money and what I do with it is my choice."
I was angry with him, and was nagging him in telling him not to get it, but what could I do? It's wasn't my decision to make, and it wasn't my money, so why should I care? I walked off.
Is that along the lines of what you were looking for? Could you provide a specific example of "invalid" nagging?