Plain shirts are great for formal occasions. The more formal the occasion, the more plain the colours required. So for example, for most people one the most formal outfits you will require is for a black tie event. For men the standard attire is the black tuxedo jacket, with plain white shirt, black bow tie and plain black shoes.
Similarly, if going to a formal setting, say a job interview, a funeral, or a court appearance, one might wish to wear a plain white or shirt with plain suit and tie. It’s a smart look and one that’s worth wearing every now and then.
However, unless you are a lawyer (or an undertaker) your work dress code probably allows for a wider range of possibilities. So you might want to build up a range of patterned shirts. For most men shirt patterns come in stripes and checks.
Striped shirts come in a variety of styles, most often combined with white. Block stripes are equal widths of contrasting colours. Bengal stripes are a thin stripes in white superimposed onto a coloured background. The reverse is also common, a white background with coloured stripes. However these are in my view not quite as iconic as the bengal stripe. In addition, shirts are of course also available with multi-coloured stripes.
Stripes are great for lengthening the torso and for adding some texture to your ensemble. Stripes combined with a Winchester style shirt are an awesome combination.
Checked shirts also come in a wide variety. Gingham check is one of the most common, in a variety of size of checks. Other common checks include the puppytooth, and the simple square. One unusual check is te prince of wales.
Checks are typically a little less formal than stripes, however the smaller the size of the check the more formal the shirt.
On good quality shirts you should expect the stripes or checks to match along a breast pocket if fitted and the button placket at the front of the shirt. The best quality shirts will match patterns between the shoulder yoke and the sleeves as well.
Ideally, patterned shirts should be combined with plain rather than patterned suits.
So if you are looking for a conservative and formal look stick to plain shirts. But on those occasions when such formality is neither required nor desired mix it up with a patterned shirt.