2. Pretty Plaids

Price: $33.90 at shop.nordstrom.com
Plaid pants, jackets, shirts, and so on, are excellent on Casual Fridays. Something about the pattern is so chic, yet casual too. It doesn't have to be evocative of hunters in the forest or anything like that, as you can see. Plus, it's such a versatile look, you can pair it with so many things!