Groove & feel — straight or swing

The same strumming pattern sounds different depending on how the subdivisions are spaced: evenly, or unevenly with a longer first part and a shorter second.

Straight feel — subdivisions of equal length — carries most of pop and rock. Swing or shuffle feel — subdivisions long-short — carries blues, swing, and much of soul. The difference lies entirely in how the beat is divided. That's why the same chord progression and the same pattern can sound like two different pieces under the two feels. Feel is one of the strongest genre markers there is, and it sits in a very small shift.