There is the science of meditation (which is demonstrated by the powerful and measurable effects it has in the brain and body). But there is also an art to meditating.
The art of meditating--like painting--is a process of gradual unfolding. In other words, the various thoughts, the tears, even the scratching and the shifting, can have a meaningful (and even spiritual) purpose that we may not see or fully appreciate until we reach the end of the process.
To become a more "artistic" meditator, err on the side of less control, and practice more surrendering (to the process).