A casual hairdo is a hairstyle that is easy to maintain and often requires minimal styling. The most popular casual hairdo is the shag, which is characterized by layers of hair that are cut at different lengths and often feature bangs. The shag is a versatile style that can be worn in a variety of ways, from sleek and straight to tousled and wavy. It is a great option for those who want a low-maintenance look that still looks stylish.