I never go outdoors to take photos in the daytime without at least one flash, often two. Sometimes I use it (temporarily) overpower the sun so I can control the light. For example, here is a photo of a milkweed (Asclepias sp.) seed pod that I took in the middle of the day near Naahelu, Hawaii:
Notice the black background. I had my camera set to ISO 160, 1/640 sec, and f16. This exposure was such that the sun was providing none of the light for the image. In other words, I was using daytime flash to overpower the sun. I had my voice-activated light stand (my wife in this case) hold the flash just outside of the frame. I was also using high-speed sync (HSS) to allow me to use such a fast shutter speed. I have two ways of using HSS. One way is to use a flash extension cable to allow me to move the flash off the camera, yet still keep all of the communication between the flash and camera. I use this Canon OC-E3 cable, but equivalent cables exist for Nikon and many other camera brands. The other option I might have used is the Pocketwizard MiniTT1 and TT5, which also allows HSS. I do not remember which approach I used for this photo.
Besides being able to get a black background, using a flash in the daytime can allow you to highlight a person, so they are brighter than the sky (as a way of guiding the viewer’s eye to them). For example, here is the lovely Tasheena at sunset:
How I took this photo was to use the camera’s meter to identify the proper exposure for the sunset. I set the camera so the sunset would be slightly under-exposed (by about one stop). Then I used my flash to properly expose Tasheena, and the result is the photo you see here.
Next time you head outside to take photos, take a speedlight/speedlite and do some outdoor daytime flash photography.