With the drummer, the bass is locking into the beat that establishes and drives the groove. With the bass notes, you're locking into the chord that is shared by the lead and supporting o instruments, in most cases a key note of the chord. And all this is changing at a rate determined by the tempo and in a direction determined by the tune and the improvisations of the lead instrument. The bass player is very conscious of the togetherness of the group and how much everyone is on the same page and constantly striving to make it better. What an experience in sharing the experience of making something joyful happen!