Some can't or won't do it because it is so personal. God forbid that someone might think us holy or religious or something. Maybe we need to reduce our expectations of prayer, loosen up a little, be kind to ourselves, re-evaluate whether or not we're imposing unrealistic demands upon our prayer life, making it seem like too much work. Rejoice always, pray constantly, and in all circumstances give thanks. These are what some have called the marching orders or standing orders of the church, found in Paul's letter to the church in Thessalonica.
Christians are joyful people.
The mark of the Christian is a kind of joy which is deeper than happiness. Joy is a state of grace that is given by God even in the midst of horrible grief and sorrow. Joy is rooted in the love and grace that Jesus showed us is in the heart of God. And the mark of a healthy church is the joy of its members. You can walk into a church and know whether or not there is joy.