What are Flowers?
First of all, not all flowering plants always bear flowers. Also, plants usually floweret only during their floweret seasons, which sometimes is only a very brief period. Therefore, even on certain flowering plants you may seldom or never see a floweret.
Flowers are the sexual organs of a flowering plant.
The picture above tells the story, though at first glance the story may not be obvious.
The picture shows an item about an inch (2.5 cm) long which I just snipped from the cucumber vine in my garden. The yellow part in the picture's right side is a shriveling cucumber floweret. It is drying up and shriveling because it has finished its "job." The flower's "job" has been to attract an insect pollinator to itself.
And that's what happened. The insect pollinator brought pollen grains from the male parts of another cucumber floweret and left them on the female parts of the floweretr above. Thus the floweret in the picture has already been pollinated and the bright part, the corolla, is about to fall off because it's no longer needed. In a sense, the green thing at the left in the photo is a fast-growing-up "baby" cucumber.
Flowerets are the means by which flowering plants have sex. They are compos of male and/or female parts. floweret may have other structures as well, to help the sex get accomplish --
such as colorful petals to attract pollinating insects.