Why should we make dua to Allah subhanahuwatala?

Why should we make dua to Allah subhanahuwatala?

We verily created a man and We know what his soul whispereth to him, and We are nearer to him than his jugular vein.(Quran 50:16)

"Verily your Lord is Generous and Shy. If His servant raises his hands to Him (in supplication) He becomes shy to return them empty" (Ahmad, Abu Dawood, Tirmidhi)

Whoever does duaa to Allah, Allah fulfills his seeking or in exchange averts misfortune until the duaa is not related to sin or breaking some relation." (Tirmidhi)

Every lawful supplication that a believer makes unto his Lord Most Gracious, is heard and answered by his Lord; for Allah is indeed All Hearing, All Knowing.

Allah says in the Holy Quran Chapter 2 Surah Baqarah verse 186:

And if My servants ask you, O Prophet, concerning Me, tell them that I am quite near to them. I hear and answer the prayer of the suppliant, when he calls on Me. So let them respond to My call and believe in Me. (Convey this to them), perhaps they may be guided aright!

The All Knowing, All Wise Lord Knows what is good and what is bad for us; therefore, if one asks for something good and lawful, Allah will give him/her one of three things:

1. Allah will give the believer what he/she has supplicated for.
2. If what the believer is asking is not good or harmful for the believer in this world, Allah will store it for him for the world of the Hereafter.
3. If what the believer is asking is not good or harmful for the believer in this world, Allah will turn away from the believer an equivalent amount of evil.

Al-Tirmidhi Hadith 2257 Narrated by Abu Sa'id al-Khudri
The Prophet (saws) said, "Any Muslim who makes a supplication containing nothing which is sinful, or which involves breaking ties of relationship, will be given for it by Allah one of three things: He will give him swift answer, or store it up for him in the next world, or turn away from him an equivalent amount of evil." Those who heard it said they would then make many supplications and he (saws) replied that Allah was more ready to answer than they were to ask.
Nu'man b. Bashir reported that the Prophet (saws), said, "Verily supplication is worship."
Narrated by Ahmad and Sunan.
Abu Hurairah reported, "The Prophet (saws) said, "Nothing is more dear to Allah than one's supplication to Him.''
Narrated by Tirmidhi and Ibn Majah.
Ibn Mas'ud reported that the Prophet (saws), said, "If any servant of Allah afflicted with distress or grief makes this supplication, his supplication will be accepted: 'O Allah, I am Your servant, son of Your servant, son of your maidservant. My forehead is in Your hand. Your command conceming me prevails, and Your decision concerning me is just. I call upon You by every one of the beautiful names by which You have described Yourself, or which You have revealed in Your book, or have taught anyone of Your creatures, or which You have chosen to keep in the knowledge of the unseen with You, to make the Qur'an the delight of my heart, the light of my breast, and remover of my griefs, sorrows, and afflictions'." A supplication in these words will be answered. Allah will remove one's affliction and replace it with joy and happiness.
Salman reported that the Prophet (saws), said, "Your Lord, the Blessed and the Exalted One, is Modest and Generous, and He loathes to turn away His servant empty-handed when he raises his hands to Him in supplication."
Narrated by Ahmad and Ibn Hibban.
Al-Tirmidhi Hadith 2248 Narrated by Abu Hurayrah
Allah's Messenger (saws) said, "There are three whose supplication is not rejected: one who has just ended a fast, a just imam, and one who has been wronged, whose supplication is raised by Allah above the clouds and for which the gates of Heaven are opened. The Lord says, 'I swear by My Might that I shall certainly help you, though it be after some time.'"
Abdallah b. 'Umar reported that the Prophet (saws) said, "Hearts are like vessels, some more attentive and capacious than others. When you supplicate Allah you should be certain of being answered, and know that Allah does not answer a supplication that comes from a careless and inattentive heart."
Narrated by Ahmad
Abu Hurairah reported that the Prophet (saws) said, "Your supplication will be answered if you are not impatient, and if you do not say, 'I supplicated but my supplication was not heard'."
Narrated by Malik.
In light of the above aayah and the various narrations from the Messenger of Allah (saws), it is evident that no lawful supplication to Allah of a believer, is ever left unanswered.

The Prophet (peace and blessings of Allah be upon him) said: "The slave will receive a response so long as his dua does not involve sin or severing of family ties, and so long as he is not hasty." It was said, "What does being hasty mean?" He said: "When he says, 'I made dua and I made dua, and I have not seen any response,' and he gets frustrated and stops making dua." Narrated by al-Bukahari, 6340; Muslim, 2735.