For those who haven't seen Knuth's own analysis of his errors while writing TeX, it's well worth reading his 1989 article "The Errors of TeX" [1] and glancing through the full chronological list of errors [2].

[1] https://yurichev.com/mirrors/knuth1989.pdf

[2] https://ctan.math.utah.edu/ctan/tex-archive/info/knuth-pdf/e...