Cities across the world celebrate Mardi Gras with colorful parades and over-the-top parties. Then Ash Wednesday arrives ... Sigh. Lent has begun. You hear about devout friends giving up seemingly innocent things like chocolate or stressing out as they try to live a more perfect life during six grueling weeks-for reasons you don't completely understand. Sermons about penitence are preached, and guilt soaks the congregation. Sound like...