Thought you'd never ask.
I was in a meeting where he spoke. I'm trying to remember where, maybe it was the Asia Society (yes, left, Richard Holbrook used to be Chairman). I was sitting with a guy who came up from DC for the meeting and we were up front, second row, if I recall correctly.
What I noticed was Zarif seemed to have picked me as a person to watch to judge how the audience was receiving his line. At one point, he was looking away from the audience, towards the wall, but I could tell he was looking straight at me. Apparently that's an intel technique, looking forward, but seeing sideways. Wonder what they call that. Anyway, I gave him a nod now and then. At the end, I didn't clap and spoke a few quiet words to the chap from DC. Glancing towards the stage, I saw he registered shock that I wasn't clapping.
I know that was strange and one might say I was imagining it, but I know it to be true, as it was obvious to me what he was doing. That was my snub. Not delivered personally, lol.
I was in another meeting with Zarif, which was actually fascinating. Oddly, it was a non-proliferation meeting. Over lunch, Richard Haass, the head of the CFR, 'interrogated' him. He had him sitting in a lone chair and he walked around him asking questions. That was when he was Amb., too, pretty early on in his tenure.