Just as I'm sure that if you all of a sudden stopped talking to your best friend that your friendship would wane. T his also receives the Divine Purpose criticism, as above, but I'll expand it beyond that. P raying for yourself has a placebo effect. Praying for the strength of will or the confidence to overcome some personal problem may well work, but not because god hears your prayer and decides to up your confidence level on his divine control panel. It's an indirect way of building self-confidence.
P raying for change in others is bit more complex.
I have had people tell me that they will pray for me to see the light, to recognise the error of my atheistic ways etc. They pray to god asking him to directly intervene and alter a person's life. There is something wrong with you. I shall ask my god to fix you and make you a better person. You should thank me for it.