UML is ass shit, and I've actively worked on forgetting it and using the brain space for something more useful like how to knit condoms for cats. Planning is good, done in a smart way that's suitable to the particular task at hand, but that rarely requires enterprise stickmen and knowing 50 different UML5.0XP2000 standard ways to draw a class in MS Visio.
But if you apply for a job in programming today, there's a 80%+ chance the person interviewing you has never heard of a pointer, thinks 'Algorithm' is the capital city of Greece and XOR is the name of that new alien movie. But they WILL babble Design Patterns BS, and rather than solve the fizzbuzz problem, they'll have you draw some UML2K enterprise pictures to show you're a good programmer.