And what about those people who don't want to hear guitar music, who prefer a quiet, reverent worship?
"Well, that's why there's different churches for different folks," said Bartlett. "And we realize that we're probably not going to reach every person."
But beyond ageism, there's more serious criticism that's now leveled at Warren and his purpose-driven churches: that the fundamental doctrines of Christianity are being mixed with popular psychology to help produce an evangelical version of "self-help."
"Well, the preaching was very much topical preaching," Owings said about the church he parted from in North Carolina. "It tended to deal with how to have a better marriage, or how to do this or how to do this. It was more self-help type ministry."
When asked if he believed that some churches had become pop psychology centers focusing too much on self-esteem and well-being, Owings said, "Yes. It's merchandising. … It tends to use psychological techniques. And it quotes more Freud, maybe, than it does the Bible."
Warren said that there is a danger in merging Christianity with psychology.
"Absolutely, there's a danger," he said. "Because what it does is feed this self-centeredness … I say, it's not about you. It's all about God. And one of the biggest myths is that all mega churches are alike. Well, they're not."
Warren also admitted that it can be difficult to strike a balance between the concerns of modern life and a focus on the Bible.
"When you're preaching and teaching the good news, you walk a very fine line where you're taking the world of the Bible and the world of today, and you're building a bridge between those [worlds]," he explained. "Now, it's easy to be biblical if you don't care about being relevant … And it's easy to be relevant if you don't care about being biblical. I happen to want to be both."
And so does Bartlett, who, at a recent church service, preached practically about love and giving out life skills to married couples. Bartlett firmly believes in using modern methods to convey old truths -- that God wants us to live an abundant life.
"I think the problem most theologians have [with us] is that we don't use the big theological words. But we talk about the terms of repentance, we talk about the terms of justification and sanctification," he said. "And so we may not use the theological terms, but the concepts are conveyed in a way that people can understand."
So the debate goes on: Is the purpose-driven method simplifying Christianity in exchange for church growth? The founder of the movement says the conflicts and divisions are inevitable costs.
"You know, I wouldn't intentionally want to cause pain to any person or to anyone," Warren said. "Am I willing to put up with pain so the people [that] Jesus Christ died for can come to know him? Absolutely."
Warren said that if some churches may suffer as a result of applying some of those principles, then "that's the price."
"Every church has to make the decision. … Is it going to live for itself, or is it going to live for the world that Jesus died for?"
When asked if he thinks that some of these splits are actually because Christians themselves are indulgent and refusing to change, Warren said, "Oh, without a doubt."
And when asked if he blames them, he replied, "I do blame them."