I think it is an evangelical thing. It's not all bad too, there are positives and negatives to it. There is something to be said about having ones prayers shaped by a prayer book or divine hours, however. I've got charismatic/evangelical friends that think its odd to pray rote prayers ,but honestly I feel sometimes their faith, their understanding of the things of God is flimsy. When one constantly approaches God with a laundry list of personal problems, it can quickly make a mess of ones spirituality.
A friend of mine when saying "grace" will often slip into asking God for things for her friends or herself... to me that's bad form. When you bless or give thanks for food, it's not the time to bring that laundry list up of things you want. I have nothing against ex tempore prayer ,but its better when it is shaped by prayers common to many Christians.