I have read so many posts relating conversations or correspondance with JW's who you think just don't "get it". After presenting what you're sure is hard evidence against their organization, they roll their eyes and shoo you away, and you walk away thinking that they're so brainwashed they'll never see reality.
I don't remember every petty negative comment I ever heard about the org, but I'm pretty sure I remember every issue of substance I came across. A householder at the door explaining John 1:1, a whispered conversation about the content of C of C, an inactive person saying they'll never come back because they discovered the "truth" wasn't the truth, seeing for myself changing doctrine.
All these things were mulled over for days. They didn't of themselves change my thinking, but they were all noted and filed away in my brain, until the time came when the file got too big to ignore, and I took it out to piece it all together. It took over 30 years, but I finally "got it".
So if someone blocks your every point with a typical JW defense and you leave thinking it would make more sense reasoning with a brick wall, you may have given that person something to think about, maybe even in years to come.