I have followed this discussion with interest as it rather touches a nerve with me, I think that all too often PCs aren't willing to engage constructively with their non-combat environment. Instead other people exist primarily to service their needs, whether that be providing goods or acting as employers. After all, that deference that so many here think that their characters can just ignore is simple acknowledgement of who holds the power - and it's not usually the PCs! Don't respect that lord because he hires a PC to deal with his problems? It might be because he's weak, but all too likely it's because he's preserving his own people and using disposables (the PCs) instead! And having used them, he's kept his own people secure (and uninjured?).
As for the setup of 'typical' D&D society, say as evinced in the DMG, I would say that it is emphatically not egalitarian! Look at the power structures it suggests. Rather it is meritocratic - the most competent and potent people rise to the top of the heap. So giving lip to that lord, or guildmaster or temple leader is just plain foolish. Likely he or she will be amongst the strongest (i.e. highest level) people in the area.
I would suggest that DMs make a point of reminding PCs that they are not living in glorious isolation in the world. They may be powerful, but they aren't the only movers and shakers. Indeed in the big picture, if they make a point of crossing the powerful, they are may be strong, but they are going to end up friendless and thus at the mercy of enemies.
As a person, you might not like the idea of social hierarchy. Fine, the worst that can happn to you is that you get passed over for promotion or shown the door first on a downturn, if you don't show deference to your superiors. But in a fantasy world the character, as misfit and friendless, faces assassination, judicial challenge, inquisition or just plain casual murder. So swallow that pride a little, and remember that the guy in charge holds on to power for a reason!
