It took you seven days to think of that retort? Witness Harlander's lightning wit in action!
Touché.
(Or your DM is terrible for making six hour sessions of nothing but combat)
Well, yes, that particular GM was the worst example of the craft I've ever experienced, even when combats weren't being stretched to last a whole half-day session, so it doesn't stand up all that well as a general case, but my terrible GM and your mumbling, inarticulate nerd herd are both extremes on scales.
The larger group of people who are less confident RPers can be encouraged by minor mechanical bonuses into improvisation, and yes, even stunting - and these things enhance my enjoyment of combat greatly. (If players feel they have to ham up every action, the bonuses are probably too big)