The casual shirt is by essence more relaxed, and the finish of the shirt reminds us of that. Cuffs and shirt-tails are curved for a more informal attitude. The stitching of the buttonhole is also visible, to give a less precious finish. Moreover, the collar is suppler and has more shape options (button-down collar, club collar, band-collar, Italian collar, classic collar).
Casual shirts offer a bigger variety of textures: chambray, oxford, poplin… the list goes on! Patterns and prints are more daring as well, and contribute to putting the spotlight on the originality of those who wear them.