Quote 1
[The Miller] swoor, "By armes, and by blood and bones,
I kan a noble tale for the nones,
With which I wol now quite the Knyghtes tale."
(Miller's Prologue 17 – 19)
By demanding that he be the one to tell the next tale, the Miller not only upsets the proper social order the Host has indicated he plans to follow, he also sets himself up in direct competition with the Knight. It would have probably seemed a little ludicrous to a medieval person that a Miller would think he could compete with a knight, even if only in tale-telling, but that's all part of the fun.