Hanging t-shirts in a closet is so weird to me. I guess I just never had enough closet space, because that's always been reserved for pants, flannels/button-ups, and sweatshirts. Sweaters get folded too but I set them out on a special place under my closet clothes.
I've done a lot of 5Ks and such, so I have SO MANY t-shirts. It's getting upwards of 50 now I think. No way I'd have closet space for that.