Cast all your anxiety on him because he cares for you.
1 Peter 5:7
God wants us to pray to him because he loves us and wants to care for us. Good parents know what's best for their children. When we have children and are responsible caregivers we want to protect them from harm and provide for their needs. Children who know that they have parents who love them are not afraid to go to those parents and tell them when they have a problem or ask them for something that they need. If those children have grown in the right relationship with their parents, they trust and obey their parents. The children may not always understand, but when they learn to accept what their parents tell them or decide for them, then their understanding eventually becomes more clear and logical to them as they get older. God is our Heavenly Father and since we are his children He cares about what happens to us. God knows every need that we have, but at the same time he wants us to understand where we come from and who provides for us. God wants us to recognize and acknowlege Him and our relationship to Him.
... I will do whatever you ask in my name, so that the Son may bring glory to the Father. You may ask me for anything in my name, and I will do it.
God wants to provide what is best for you. But it is important for you to know what is best for you. Some people hear these words of Jesus and think that they can ask for absolutely anything and get it. Like spoiled and ungrateful children they may become sullen and angry when they don't get their ways immediately. They are disappointed that God didn't give them something that they prayed for and may think the words of Jesus are not true. There are some important facts to keep in mind. Firstly, Jesus said "ask in my name". Are you asking for something that is appropriate to ask in His name? Secondly, are you on God's timetable? Just because you don't get your prayer answered right this moment doesn't mean you are not going to have it answered. Maybe you aren't ready yet or the timing is not quite right. Have faith--if the request is fair the answer will come in God's time. God can do anything. We are not limited by God's power, but we are limited by our inadequate faith and the things we ask for in God's name.
…the Spirit helps us in our weakness. We do not know what we ought to pray for, but the Spirit himself intercedes for us with groans that words cannot express.
We should pray to God for we are weak and He is strong. That is what many of us learned when we were kids and it is all too true even as adults. So often we find ourselves confused and unsure where we are headed in life. Problems may assail us that are beyond our comprehension. We may be beaten down and demoralized. That is a time to pray for the Holy Spirit to come upon us and give us strength and guidance. In those uncertain times, pray to God so that He can comfort you and open your eyes to show you the way.
If we confess our sins, He is faithful and just and will forgive us our sins and purify us from all unrighteousness.
1 John 1:9
Why should we pray? We might as well ask why should we wash our hands or why should we take a bath. We should pray because we all sinners and we are unclean. We need to acknowledge our mistakes and shortcomings directly to God and He will lift the heavy burden of sin from us to make us free. Forgiveness is necessary because somewhere deep inside we know when we have done wrong and that knowledge will wear us down eventually if we don't let God administer his forgiving spirit. When we go to God with humility and reverence and become closer to Him, He will cleanse us from unrighteousness and mend our brokenness. As a whole Godly individual our prayer power grows even stronger.
The prayer of a righteous man is powerful and effective
In becoming cleansed and righteous in God's eyes we turn ourselves over to him in obediance and faithfulness. We are saying that we trust God wholely to provide what we need and to give us guidance to do what we need to do in order to receive God's abundant blessings. We can get by on our own for a season. Psychologists may provide good insight and advice about how to live and think in order to find peace of mind and some measure of contentment in our lives. But this advice is all limited by human boundaries. If unloading some of our concerns and worries upon another mortal human being can be cathartic and healing, think about how much moreso going directly to the universal all-powerful creator.
God wants you to go directly to Him in faith and adoration so that He can have your prayers answered in the way that they are supposed to be answered and you can be given the wisdom and perception that will ultimately give you all that you need to be fulfilled and joyful throughout your life. God will not thrust your prayer life upon you, it is a choice that you have to make yourself.
Be joyful always; pray continually; give thanks in all circumstances, for this is God's will for you in Christ Jesus.
1 Thessalonians 5:16-18