The theme of Billy Collin's "Introduction to Poetry" is that readers should enjoy poetry instead of overanalyzing it in an attempt to find its meaning. Collins illustrates this theme through his comparisons between how he wishes to experience poetry and how he perceives poetry to generally be experienced.
In his poem, Collins bemoans how readers focus too much on finding the deep meaning in poetry and too little on enjoying what they read. Collins compares this to trying to "torture a confession" out of the poem. He instead recommends experiencing the poem as a piece of art rather than a puzzle, by enjoying it first and finding meaning later.