We pray according the will of God. If we pray according to our own will we pray a miss, and God will say no, or like you said, Crisi, he might say wait, and what we want to happen now, may happen later. There are times if God agreed with what we are praying it might not be in our best interest, so we must trust in God to know best and do best. There are times that we don't know how to pray; we don't know what the will of God is, then we pray and say, "God, your will be done, your will not mine." There are times we pray in the Holy Spirit, and the Holy Spirit third person of the trinity knows the will of God, and He will pray through us. Often our praying is with groaning, or even prayer without forming words to express ourselves. God sees all, He knows all, and He knows what is best.