Sometimes this is important to you because certain varieties of African violets do not "come true" or reproduce the same sort of flower if you simply reproduce another plant by rooting a leaf. Chimeras are one type of plant you must either take a sucker from OR start a bloom stem if you want the flowers to have the typical two color or striped pinwheel pattern on them.
Here you see some bloom stems just taken off the plant with the spent flowers still attached.
There is still a little flower bud on the lowest one.... that should be taken off too. The stem needs to use it's energy on making roots and not trying to open that flower.