How Much Mess Is Perfect at Home

One of this month’s Pottery Barn catalogs features a couch with a slightly saggy slipcover and a vague indent on one cushion, as if someone had sat in it and walked away. The pillows look as if they had been rearranged by the person who just left, while a pair of eyeglasses, a mug, and a slightly askew stack of magazines rest nearby on a coffee table.

“It really does look like a place you want to dive in and take a nap,” says...