Prayer does work, I agree. In my experience, however, it rarely works is a way that I infer from this sticker. In other words, I don’t believe prayer that “works” is like a “Precious moments” moment.
Abraham bargained with God. Jacob wrestled. David sang and danced prayerfully, but also wrote long laments about the sense of God’s absence, of begging God to remember His promises.
When it came down to it, Jesus was so stressed in prayer that he sweat drops of blood. (Luke 22:44)
Prayer works in part because prayer is work.