Jenna Lyons is physically demonstrative. If the creative director and president of J.Crew is baffled by a suggestion, she’ll make a baffled face. If she is shocked by the price of a Hans Wegner chair, she’ll pantomime a backward stagger. When a knit dress strikes her as drab, she’ll enunciate the word argh. Lyons is discerning, but she’s also six-foot-five in heels, and the fact that there’s an awful lot of her means that even the subtlest expressions come across loud and clear.