"When you pray, you are not to be like the hypocrites; for they love to stand and pray in the synagogues and on the street corners so that they may be seen by men. Truly I say to you, they have their reward in full. "But you, when you pray, go into your inner room, close your door and pray to your Father who is in secret, and your Father who sees what is done in secret will reward you. (Matthew 6:5-6 NASB)
Matthew 6 verses 1-18 are primarily dealing with hypocrisy, and verse 5 and 6 lead us into the Jesus' teaching about hypocrisy in prayer. It is so important to recognize that prayer is not primarily a public event. If you take this verse at face value you will see that a love of standing in the synagogues praying to be noticed gets you nowhere with God. The recognition you get from men and women for your public praying is your only reward... that is it, because that type of praying has no eternal value.
Now you must be a little careful here, it is appropriate to pray publicly in some sense, and it is appropriate to lead people in prayer, and pray in behalf of an entire congregation or people group. However prayer in the public meeting or service is not the normal mode of prayer. Moreover I often hear people saying that you should not prepare your words before you pray on behalf of a congregation publicly, I disagree. Be very careful, I would submit that a public prayer ought to be as prepared as the sermon itself. When you preach you are preaching to men, when you pray you are speaking with God. Who should you be more careful with, men or God? Also in public prayer you are going to the Most High God on behalf of a number of people, it certainly is appropriate to be prepared.
With that said, when you pray you are not praying to be seen by men, and you are not praying down a message from God, you are praying to God. You are not to come up with flowery words, or with praying that will somehow expose your theological prowess or anything else, when you pray for a people you ought to pray honestly, speaking the petitions and thanksgivings to the Lord with honest sincerity without a hint of self in them.
Look at the above passage, Jesus says 'But you, when you pray go into your inner room, close your door and pray to your Father who is in secret, and your Father who sees what is done in secret will reward you.' If you stand to pray publicly in a worship service I would hope that is not your entire prayer life. Prayer that has the ear of God is prayer which nobody but He knows about! If you tell me you are a prayer warrior (not a big fan of that verbiage) I will naturally question your sincerity. If you pray in secret your wife or husband will know because they have probably walked in on you a few times, or you have had to tell them you were going to pray, but the community at large ought to be oblivious. Hypocrisy in prayer abounds. At the same time there are likely many people in your congregation that have a very fruitful relationship with the Lord and a prayer life that has reached depths that you have yet to comprehend and the very reason they have reached those depths is the same reason you do not realize they have, it is in secret.
Just a final thought for this post, is it not ironic that just before Jesus teaches 'The Lord's Prayer' He instructs people to pray in secret, and yet in most mainline protestant churches 'The Lord's Prayer' is a public unison prayer? Hmm... that's odd.