[Was Cantor Surprised?][1] published in Monthly is debunking (or trying to do so) that Cantor was so surprised when he discovered $I=[0,1]$ and $I^2$ have the same cardinality 
that he said “I see it, but I don’t believe it!”. The abstract of the paper reads as follows: 

> **Abstract**. We look at the circumstances and context of Cantor’s famous remark, “I see it, but I don’t believe it.” We argue that,
> rather than denoting astonishment at his result, the remark pointed to
> Cantor’s worry about the correctness of his proof.

  [1]: http://www.maa.org/sites/default/files/pdf/pubs/AMM-March11_Cantor.pdf