I love my rugs, they cozy up a room and give it some extra depth and colour. They keep my feet warm in winter, too. I like that I can pick them up and clean underneath. Sand and dirt always fall through carpet fibers and collect underneath. I had such a rude awakening when I pulled up the wall-to-wall carpeting in one of the houses I lived in - there was so much sand underneath it was almost like a beach!!
With area rugs, you really need a carpet pad to keep the rug looking nice, to prevent the rug from slipping around and to avoid having the rug scratching and rubbing against the floor underneath it. Rug pads also help to keep thin rugs from bunching up and getting wrinkled.
What I don't love is cheap rug pads that stick to my hardwood floors and leave an icky film on them.