This is a Dolichopodidae, also known as a Long-legged Fly. There are over 137 species of them in Florida and 18 of those have only been found here. They are very small. Less than a 1/4 inch and even less than 1 millimeter. You will see them flitting about everywhere.
They are carnivorous and eat even smaller flies (think no-see-ums). They will often return to a preferred, predictable observation spot when feeding. When they take off, they leap backwards and I noticed they did so every time I clicked the shutter. I expect it was reacting to the movement of the lens and iris.
For this picture, I set the focus point on the edge of the leaf to the right and waited for a fly to return to the leaf. I set the camera for a fast series and started shooting. Eventually, I found a couple worth keeping.