I am usually at a loss in temples. In North America temples have large number of deities. What am I supposed to say when standing in front of each deity?
I do not visit temples unless I go with someone because they want to go. I have no desire to ask God for anything. I think whatever eventually happens is outside of my control and wishes but I do what I can when I have a choice or have to make a decision. So I do not know what to pray for.
I once saw a man and his son do sit ups 10 times in front of every deity!. There are people that go around Navagrahas and do Namaskaram while someone told me to just walk away after going around 3 or 9 times .
My question to you is - what do you tell yourself or ask God when you pray ?
How do you pray? Why do you pray? Why do you go to temples when you have a puja room?
As you have asked for a composite answer, I attempt to give one to the best of my knowledge and belief.
1. Prayer is defined as a reverent petition made to God or an object of worship, so it is in the form of earnest plea.
2. That said, in Hinduism, prayer is defined a bit differently. It is basically not a prayer, but participation in actual or symbolic worship. The recitations used in the **prayers** are "stotrams" or "stutis" (that is hymns of praise), or "mantras" (mystical compositions) of "japam" (repeated recitation of a portion of stotram or a slokam or a mantram to internalize it in the mind).
3. Having said point #2 above, some of the "stotrams" contain an appendage of what is known as phala-shrutii, that is what the Bhakta can expect to get in return for his participation. The phala shruthi is considered as **artha-vAdA** meaning that it is a sort of inducement or exhortion for the religious act. So there is no guarantee that the required phalam may materalize.
4. Why do people pray for, is summarized by yourselves in the second para of your post. So many things are outside the control of human beings, but those forces also affect the life and livelyhood of the person praying. So praying sort of asks the support of the Almighty to the person offering prayers.
5. The second way to look at it is, in Hinduism the Almighty is considered to be the father & mother of the person offering prayers and the Almighty is assumed to be the controller of the whole universe. Just as a child beseeches its parents for its wants and needs, people ask the Almighty to fulfill their wants.
6. I would consider it as an act of egoism when people say they have no wants to be fulfilled by the Almighty, but would still go to the temples to pray. If they have no wants why do they strive in their lives? and if they think that Almighty cant fulfill them their internalization doesnt make the God they pray to, an omnipotent entity. So many things in life, including birth itself is acquired through mere **chance** which are beyond the ability of an individual to acquire all the things he or she posses or come to posses by his/her meticulous planning. This would bring in the concept of namaH or na-mama, which is beyond the scope of this thread.
7. If you have missed a point, unlike other religions we go to temples more for **Darshanam** of the Lord or to make our eyes and mind to take in the beauty of the Lord, having attributes and physical facilities as described in our scriptures and reigious texts. That is why the **moorthis** or **vigrahams** are made or carved out so beautifully by the artists. In so many of the temples, it does give **Aanandam** to capture the majestic beauty of the Lord in the eyes, though one may be skeptical to think it is just an imagination of another person.
8. Doing sit ups or **thoppu-karaNams** is an act of contrition or seeking forgiveness for the wrongs committed by the person, so they are akin to the "confessions" made to the priests by christians. The underlying theme is that the body is made malleable to the will of the Lord just as mind is supposed to have already been made receptive to His suggestions by repetitions of stotrams, mantrams etc. and the like.
9. One another point which you appear to have missed out, is the act of taking **prasAdam** of the Lord after participation in his worship symbolically. Yes, when you visit a temple, you have symbolically participated in the **pooja** of the Lord conducted by the poojari. Thats why we go to the temple after having obtained the minimum cleanliness required of the body, like after bath etc.