The thing that doesn't work for me in Agile: being treated like a baby and spoon fed little bits of work with little room for responsibility, initiative, creativity and a personal touch. Agile is great if you are a mediocre manager and you want to run a place full of replaceable cogs, but not so great if you want a place that pushes the boundaries and consistently goes the extra mile
But, of course (almost) no one does scrum cause sales/customers want up front signed contract listing exactly what will be done and exactly when.