Luke 5

Lk5:8 When Simon Peter saw it, he fell down at Jesus’ knees, saying, “Depart from me, for I am a sinful man, O Lord!”

How would the story go on, if Jesus would do what Peter asked him to do: to depart from him. If Jesus departed from him.... I'm not sure, if Peter would have become Jesus disciple, following him. Then the stories in the bible might have been totally different.
Of course for God it is not difficult to find another disciple, replacing Peter (We know that God would still fulfill his will somehow).
But for Peter it would have been a pity, if he couldn't follow Jesus. He might not get this chance again, to follow Jesus, to walk on the path of righteousness and truth. He might have continued in sinning.
However, Jesus wanted to choose him as one of his disciples and so he told him:
Luke5:10“Do not be afraid. From now on you will catch men.” (Lucky Peter...)

For us it is similar. Often God does not answer our prayers or he does not act in the way we want him to act.
But thanks to God, that it is like that. Because if he would answer our prayers immediately in the way we want him to answer, then I don't know, if that was good or bad for us.
For whatever God does, it is to help us but not to harm us. Writing this I think of a very famous verse in Romans:

Rom.8:28 And we know that all things work together for good to those who love God, to those who are the called according to His purpose.