I think a lot of what makes prayer seem foolish to some is the way people use it. Most people seem to see prayer as asking God for something. While this is something you will find instructed in Judeo-Christian writings like the Bible, it is a far too simple and somewhat ignorant understanding of the concept of prayer by even some very “religious” people.
The epitome of prayer is considered to be not asking God for something and having the prayer answered, but as great mystics have taught, communing with God in order to lose self and serve others. As Teresa of Avila once explained it, once when she was traveling by donkey on a mission, she was thrown from the beast after crossing a rocky riverbed. She claims Jesus told her: “This is how I treat my friends.” To which she replied: “And that is why you don’t have many friends.”
Mystics like John of the Cross, Teresa of Avila and others teach a very different type of prayer than what is being discussed and advocated in religions. Hopefully some of the bright points brought out here on this board in these discussions will help people see that it often isn’t prayer or God that is useless, but often it’s us who are so self-centered we only want our needs fulfilled or want our viewpoint to be proven right. When prayer doesn’t work according to some preconceived ideas (like held within the Watchtower) prayer suffers the blame instead of the definition of "what it should be."