I'm pretty tolerant of it but I can only take so much before it is plain the person is just trolling. Some people do this because they are just space cadets with ADD but when the tone is very harsh and repetitive, it can't be ADD so that's the point at which I decide.

I have the patience of a saint when it comes to training and teaching, especially if I am being paid. But I think any teacher would rather not take the money, all else being equal, if the student is being contrary to amuse themselves. Whether it's teaching or simply discussing something that the subject simply does not know that much about. At a certain point with that guy, it became obvious he wasn't interested in reading about it, just telling me his opinion about whatever I said last, usually out of context.