When we talk about music as musicians or as listeners, a fundamental principal that draws our attention is groove. What is groove? You may think of it as the beat of the song that really gets you going; that thing that makes you want to dance or nod your head to the beat. But its much deeper than that. Groove lies beyond just the beat or the time signature. It is how the song sways in relation to the fundamental percussion. That push or pull that a good drummer can accomplish to create or dissolve tension. See the video below as reference: (pay close attention to the relationship between the drummer and what the harmonica is doing).
As harmonica players of all levels, our focus should be not so much on if we can accomplish bends,overblows,overdraws,warbles,( or much of the other harmonica geekery), but rather on the fundamental groove. Technique is anchored by fundamentals, groove being an essential element to the foundation. Here are a few videos from other schools of music to chew on in the furtherance of playing in relation to groove.
In the above video, groove is used in the solo context. Pushing and pulling of the beat is completely defined by the performer.
This song is a good study of the relation between minimalistic rhythm guitar, a drum pattern, and most importantly what the bass is doing. Harp players take note.