Depending on the shutter time a picture’s subject can give a different result. Where a short shutter time freeze the image a longer time can bring the impression of movement. For the longer shutter time one need to take the amount of light in account. A longer shutter time can overexpose images. That is why an lower iso and a high aperture is an absolute nessesity. Even a grey filter or a progressive dark filter can bring solution to the problem of overexposure.
On the opposite an image can get a freezing aspect. Below an example during a misty day where raindrops forms magnificent splashes.
In both images water is the subject. If you catch an appropriate subject, always take both sides of the mirror. You always decide later which one to hold. Anyway not all subjects are suited for both intakes. It always the photographer to decide…