Five-year-old Swedish sock brand Happy Socks opens its first U.S. store on April 5 (436 W. Broadway, nr. Prince St.; 212-966-9692). Among the 70-odd unisex styles just begging to dress up a conservative work look: jaunty argyles, wild stripes, trippy polka dots, and neon animal prints in crew, knee-high, and ankle lengths, all woven in breathable combed cotton and retailing for $12 a pair. Also for sale are zany options for babies (six pairs for $30) and the last remaining stock from the brand’s sold-out collaboration with Keds, which includes an Americana-themed set of socks with matching sneakers ($65).