When I say casual, I don't mean no suit jacket required. I mean I rock my skinny jeans and t-shirts, and try to look somewhat acceptable with cute jewelry, sweaters, and in toning down my bright wonderfully clashing style just a bit.
Which is why I can't live without these! Nordstrom Frenchi® Boyfriend Tee (Juniors)
They are sooo comfy and soft, come in every amazing color (of which I have 4+), and are juuuuust a little nicer than a regular t-shirt. (Shut up, they totally are!) Therefore, I fully consider them work attire under a cute cardigan.
Go buy one today!! Or four.