Dear PMV,
From the master of prayer, St. Teresa of Avila, we learn that prayer is a movement of the mind and heart to God, which can often be wordless - just a loving attention to Him, a quick glance of love.
Whether we read words of prayer or recite from memory, we should strive to have the same loving attention, fully meaning the words we speak to God, St. Teresa advises, because we are in the presence of His divine Majesty!
It sometimes happens that with our best intention of remaining focused, we suffer distractions - part of the human condition. She tells us that the will is captive, but our understanding has wandered. The will is praying effectively for us with the intention we have of giving honor and glory to God in our prayer.
Have you noticed these sidetracks while praying the mass? It happens often, but our mass prayers are still effective because we wanted to be there. Unwilled distractions are not displeasing to God. Many who pray the rosary will notice that their thoughts stray, but if they recall them back to task and continue in the intention of prayer, they are heard. One does not have to start it all over again, or hear another mass if their thoughts were not 100% centered.