Like many have commented, out of all the meetings I find the Watchtower study the most annoying, often for the content, but certainly for the way it is conducted usually.
Reading the paragraphs of the Watchtower - it's mostly pointless and wastes everyone's time, as is demonstrated on the circuit visit when the paragraphs aren't read anyway. And as has been commented on already, most of the answers are just reading out the paragraphs AGAIN.
Some conductors also can make the Watchtower more annoying than usual too. I find it annoying when they ask too many specific auxilliary questions, trying to extract every little snippet of the paragraph, effectively having the audience read out each bit again. It leaves no time for "discussion" or "expanding" on anything, and kills any possible usefulness of the already wasted time.