Park Benches

I attended our church's Convocation today.  Dr. Tom Long from Candler was leading a day long session about preaching. 

He talked about how some people experience a sermon as a series of isolated episodes -- park benches.  Sometimes they find one that interests them, and they sit down a while and explore it.  Other people experience a sermon as a series of thoughts leading to a conclusion. 

One of the goals of a preacher is to try to teach listeners to follow the complete line of thought, all the way to the end, rather than taking breaks along the way.

Are then benefits to park benches?  Is it sometimes good to take a break during a sermon and wander off to explore our own thoughts?  I can see how God would work through both of these experiences.