For me, growing up in perhaps the blandest version of mainline liberal Protestantism, Lutheranism, far from being boring, seemed wonderfully exotic. All of that medieval-style chanting; people thinking they were eating Jesus’ body and drinking His blood; having beer at church dinners. On that last point, both the liberal Christianity I grew up with and the conservative Christianity of some of my friends tended to see smokin’ and drinkin’ as the prime example of sins. But Lutheranism cared little for these little life-style issues (indeed, seeming actually pro-alcohol). That blew my mind, as we said back then.
But I think I know why people might think Lutheranism is boring. It’s the Lutheran doctrine of vocation.