I think that the fact that he was enthusiastic about his subject and clearly wanted to tell people about it came across as unpleasant or pushy or something.

I thought that just made it better - people who are interested in what they're talking about and want to tell you about it tend to be more interesting than those that just do it because they need to.

The jokes and gestures seemed studied to make an impression. It didn't come across so natural. But it did not bother me too much - I don't like being manipulated, but his words were entertaining enough, therefore the "OK" verdict.