Why did Jesus teach people the 'our father' prayer?

One thought:
Because Jesus' disciples (some formerly John the Baptizer's disciples) asked him to teach them to pray(Luke 11:1). At Matthew 6:9-13 (Luke 11:2-4) Jesus provided a 'sample' of what to pray about, putting God's interests first....Glorifying God's name(Psalm 83:18)and thanking him for the things we appreciate, his promise of his Kingdom(Daniel 2:44/Matthew 6:33/Revelation 11:15), which will cause his will to be done on earth(Isaiah 11:9/Psalm 37:11+29/Matthew 5:5).... Then we can pray for help in dealing with other people (Ephesians 4:32/1 Corinthians 13:4-7/Colossians 3:13) and for our needs to be met(Philippians 4:6+7/1 John 3:22/Mark 11:24/Ephesians 3:20/Psalm 5:1+2). All proper subjects for prayer....
Jesus, however, made it clear that these Words were not to be repeated over and over, from memory, because Matthew 6:7&8 tells us: "...when ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking.

Be not ye therefore like unto them: for your Father knoweth what things ye have need of, before ye ask him."(KJV)

(1 Kings 18:26)

God wants personal prayer 'poured out' (Psalm 62:7+8)from our own mind and our whole heart(Psalm 62:8/Psalm 142:2). He already knows what we're thinking, but he WANTS us to ask...to TRUST in him as the 'hearer of prayer' (Psalm 65:2/Psalm 34:18/Psalm 55:22) and as the one who will fulfill our needs(Psalm 145:18/1 John 5:14/2 Corinthians 1:3+4).