The funniest code review comment has to be a song lyric from an earlier job (a Justin Bieber song, not too proud about that :P).

So, my reviewer asked me to change something, but later I explained to her that whatever I had done was correct. The first comment she made on my PR was rather aggressive and once she realized that I was actually right, she commented again saying "Is it too late now to say sorry?" :D

I can't find the email right now but at one time my client wrote (to another team member) something like:

“…I'm pretty sure mobile-optimized HTML comes shooting out of his fingertips…”