Excerpt from my email to him:

Second, I said at one point that, "...a handout was given to supplement the text, with 
instructions that generally served more to elucidate the original procedure than change it." 
To which you responded, "please try to refrain from complaining in write-ups, better to 
complain about it in person." I don't see how this could be a complaint, as "elucidate" 
simply means "to make clear" and if the lab was clear enough as-is, a supplementary handout 
would not have been given. While you were explaining the lab I had a thought in my mind as 
to the role of this extra handout. Should it replace the text? Or is it simply a supplement? 
You answered that question without me asking. Nevertheless, we can assume that if lab reports 
are to be written as though they're directed at people who don't know everything we know, they 
would probably be curious about the role of the additional handout as well, and it's doubtful 
you would be around to clear things up. Therefore, I felt the need to explain the role of the 
handout. If it sounds like a complaint to you, I understand, but it's not and I'd like to know 
how better to word it if you still think so.

Excerpt from his email to me:

I apologize about the comment about complaining, sorry. It was more just an underlying feeling 
that I had gotten from reading the lab and I guess when I re-read that part when making comments 
I put it next to the first part I felt was a bit negative. Your description here is ok.