Some are a little petulant:
Mathematics my foot! ... Programming is much much harder than doing mathematics. I bet that the referee will never ever be able to write such a program.
Some more forlorn:
With high optimism, we submitted a paper to a top-tier image processing journal. ... But alas, our enthusiasm was deflated due to the following review points...
And some kind of funny:
Our obsession with these simple matrices has generated a great deal of criticism. Lubos Motl, the string theorist, called us F–ing Crackpots on my blog ...
and
Where did I go wrong? Perhaps I should not have called professional mathematicians, in the first paragraph, “meaning-imposers” who generate “inconsistencies and confusions”. Perhaps I should not have asked “Where did I go wrong?” on page 61; or, “Have I made another blunder?” on page 62. ... Maybe I used too many exclamation marks.
It's hard to do them justice as a whole, so I suggest you read them for yourself!