Your director is not a boot-camp sergeant
... but his or her directions are vital to making a song musical and coherent. Your director will guide you in
- dynamics (the loudness or softness of a piece)
- mood (the overall sound of a piece)
- entrances at the beginning of a piece or tricky line starts
- endings (or cutoffs) of lines or verses
- breaks for instrumental verses
- and much more.
Follow your director meticulously to avoid mistakes.