I often have made impassioned, reasoned arguments with detailed lists of reasons for my conclusion only to receive a short, pre-programmed reply in return that clearly shows the theists didn't really hear what I said. This is comparable to arguing with a broken record--it hears nothing and keeps repeating the same thing over and over.
This is especially frustrating when you are dealing with educated theists in positions of power or authority who are exactly the sort of people who should be able to pay attention to an argument that takes longer than 7 seconds and who should want such arguments to be made so that they are well informed.
A recent study confirmed, however, that one of the best predictors of whether a person was religious or not was his or her ability to absorb new information. Thus, even well-educated believers simply cannot absorb new information quickly unless you package and present it for them in a very memorable manner.
A new book has appeared which further confirms this phenomenon. "The Religion Virus" by Craig A. James explores the ways in which memes survive and propagate based on the frailties and peculiar characteristics of the human mind. One of his most important points is that the truth value of a meme is far less important than its catchiness. Here is a quotation from a review of that book that appeared in Secular News Daily:
"In a delightfully ironic anecdote, James uses the popular meme “survival of the fittest” to illustrate that truth value is not as important as “catchiness.” Survival of the fittest is a vague and ultimately inaccurate way to sum up natural selection. “The correlation between specific genetic characteristics and reproductive success” is much more accurate, but it’s much harder to remember, and much less appealing. It just doesn’t roll off the tongue."
There may be suggested arguments in some of my posts that don't meet that criterion perfectly, but feel free to shorten them to their essence when the occasion arises. You will almost certainly have to tailor many of them to fit the particular conversation in any event.
Religion survives to this day because it presents short, simple answers that are easy to understand by anyone and that resonate with the common human assumptions about the way the world works. Your counterarguments have to do the same or they will never even be heard.