For me the public talk was the most boring, it was just too long, and it was rare that a skilled person gave it. In real life most of the persons would never qualify to give a public speech. The talk was unstructured, it had no sense of direction, and you just couldn't link one part to the next, like there was a big bump between them, all unconnected.
I guess they usually took the outline, and gave meat to all points separately without consideration as to what is the main purpose of the talk, and have it all converge to it, or at least link the different parts somehow.
There were some who were truly great, and it was not only my personal assessement, but I remember hearing whispers in the congregation: brother X is giving the talk? Oh, I'm so glad, this will be so interresting.
The TMS / Ministry was a bit better, because at least there the talks were short, and before you truly got bored of it, an other one came (just as boring, but at least differently boring). Watchtower study required active participation (for a long time I carried the microphone, so that was ok), and on the Book study because of the size I felt sort of like a true christial fellowship, that I had usually not felt in the KH.
That said, I left them all at once too.