It also has to do with the way you feel and express time.
Think of a beat. You can play directly on the beat.
Or you can play slightly ahead of the beat - a lot of trad jazz does this, (as did punk) and it gives a driving sound.
Or you can play slightly behind the beat - think Motown and R&B.
If you're playing ahead of the beat (pushing time) and the drummer is behind the beat (trying to groove) then the rhythm section sounds crappy.
If you and the drummer are feeling and expressing time the same way, then it "locks in".
Once in a while you meet a drummer who naturally expresses time the exact way you do. When you meet him you KNOW it. Everything locks, and people start asking what you guys charge as a rhythm section.
