Pastor Hosang, why should I pray?
Why communicate with your best friend? Obvious reasons are that you love each other, enjoy hanging out together, and delight in knowing and being known by someone special. Occasionally, you ask them for something or for help, but this is definitely not the full extent of your relationship.
Sadly for me and perhaps you, our communication with God sometimes becomes a shopping list or 911 call, without any personal adoration, thanksgiving and confession. The Psalms and "The Lord's Prayer" provide us with examples of the diversity of prayers and their components, though prayer is not merely a religious exercise but a loving communication with God, our Father and Friend.
Two obvious difficulties in praying are that we find it difficult to communicate with God whom we cannot see physically, or when life's good and we don't feel the need to pray. One negative difficulty occurs when God disappoints us by seemingly being silent or deaf. When we don't feel like praying is when we most need to pray, because our enemy wins whenever we sever communication lines to our all-knowing, all-powerful, all-loving Commander in Chief. Times of God's silence are opportunities for us to develop deeper intimacy and closer alignment with Him and His purposes.
Like me, hopefully you are learning the strong correlation between your growing prayer communication and your growing personal relationship with God, often catalyzed by times of your real and felt desperate need for God.