At least some of this confusion stems from the term "worship service." Since people attend these ceremonies, they think this is when "worship" happens. It is all one big confusing mess. The reason for all this, of course, is that worship is not why the church gathers (worship is a 24/7 exercise). Rather, the church comes together for mutual edification.
I Corinthians 14:26 is an extremely important verse. Paul writes, "What then, brothers? When you come together, each one has a hymn, a lesson, a revelation, a tongue, or an interpretation. Let all things be done for building up." Paul is less concerned with their specific activities than he is with why they are doing what they are doing. All should be for the building up of the body into maturity in Christ. We see an active body where each person uses his or her gifts to build up others.
Mutual edification is easy to define. Because of that, it is easy for local bodies of believers to make this the focus of their gatherings. They can step back and see if what they are doing is actually accomplishing what it should. On the other hand, when churches focus on worship, it is nearly impossible to determine what their meetings are accomplishing.
Before even gathering together churches should ask the "Why?" question. The answer to this question is much more important than the "Who? What? Where? When? and How?" questions. If a church doesn't know why it comes together, then none of the other answers matter.
Simple churches meet for mutual edification of the body. It's as simple as that.