[Zigûr]

Originally Posted by Inziladun

Oddly enough, either Shagrat or Gorbag (don't have my books at present) remarks of Frodo's "great" companion that he apparently didn't value Frodo much because he just left Frodo lying there in the tunnel. It's interesting too that he calls that sort of behavior a "regular elvish trick". Was he referring to the failure to try and save Frodo, or not properly disposing of the body?

Just checked, it's Gorbag.
As for a "regular Elvish trick", when's the last time Gorbag, a Morgul-Orc, dealt with Elves? Unless, I suppose, we ascribe to the theory that Orcs are long-lived.
Snaga also talks about "bloody-handed Elves, or one of those filthy tarks" so perhaps they had an ingrained antipathy for Elves and the Dúnedain: propaganda or a symptom of their corruption.
Gorbag also describes Sam (thinking him to be "a large warrior... Elf most likely") in this way:
"there's someone loose hereabouts as is more dangerous than any other damned rebel that ever walked since the bad old times, since the Great Siege."
I might be reading too much into one word, but does the use of 'rebel' suggest that Orcs thought of their enemies as 'rebels' in general - rebels against what was bred into them as second nature, that the Great Eye was the natural and rightful lord and master of the world? We are told in Morgoth's Ring that after Morgoth's defeat "the Orcs recovering from their helplessness had set up petty realms of their own and had become accustomed to independence. Nonetheless Sauron in time managed to unite them all in unreasoning hatred of the Elves and of Men who associated with them; while the Orcs of his own trained armies were so completely under his will that they would sacrifice themselves without hesitation at his command." This seemingly explains their attitude towards Elves and the Dúnedain, and also gives some suggestion as to why they might think of Sauron as being absolute ruler of the world with their enemies as mere 'rebels.'
The footnote to this states that "But there remained one flaw in his control, inevitable. In the kingdom of hate and fear, the strongest thing is hate. All his Orcs hated one another, and must be kept ever at war with some 'enemy' to prevent them from slaying one another."
It's a sentiment very evocative of the notion of 'War is Peace' from "The Theory and Practice of Oligarchial Collectivism" in Nineteen Eighty-Four.
Additionally, does mention of the 'Great Siege', assuming Shagrat and Gorbag aren't old enough to have witnessed it first hand, suggest a reasonable concept of history in orc culture?
I've often wondered how much the characterisation of Orc characters in The Lord of the Rings is reflective of the degradation of human dignity and "coarse behaviour" of soldiers under extreme stress and in terrible conditions in the First World War. Letter 66's mention of "huts full of blasphemy and smut" has always resonated with me in this regard.