Here's one that irritates me:
Babylon the Great has to be a "religious" entity because she committs fornication with all the kings of the earth.
"Jehovah will turn his attention to Tyre (a political not a religious entity) and she must return to her hire and commit prostitution with all the kingdoms of the earth upon the surface of the ground"
Isaiah 23:17
Their whole argument identifying Babylon the Great as the World Empire of False religion is fallacious.
Go ahead write them and point this out. They are defenseless. You'll probably get a Dear Fellow Worshiper letter, telling you to get out in service, keep praying, and studying their (stupid) arguments over and over and over and eventually you will see that they are right.
Everyone has their favorite complaint about the Watchtower mistakes.
But you have to ask if you believe (big IF) that Jehovah is in charge and there are myriads and myriads of angels directing the work why can't they can't take a peek in the kitchen where this horrible food is being prepared.