In brighter situations, you have a lot more flexibility to use a faster shutter speed, narrower aperture, and lower ISO.
Now for how these factors relate to each other. A properly exposed image is produced when shutter speed, aperture, and ISO are balanced with the ambient light. In darker environments, shutter speed must be longer, aperture must be wider, and ISO must be higher. In brighter situations, you have a lot more flexibility to use a faster shutter speed, narrower aperture, and lower ISO.