The prayers that sounded like they were teaching Jehovah something. As if he didn't already know whatever they were saying. "Jehovah, we learned tonight about the point of....and then we were instructed on ..... and we then learned about...."
Or
The prayers that were simply a review (or preview) of the entire meeting! I would stand there thinking "Yer yer...I JUST heard all of that, you don't need to give us (and god) another summary of the exact same stuff!"