Praying selfishly?

In her book Eat, pray, love, Liz Gilbert explains how her understanding of prayer is challenged.  During her gruelling divorce she prays often, but doesn't feel it right to ask God to change her situation. Her thinking is that, if she is going through difficult times, maybe God wants her to go through them, in order to learn something.  Praying for God to change the circumstances seems like a weakness of faith.  Instead, she prays that God would give her the strength to cope with whatever life throws at her.

A friend tells Liz that this is stupid - that it is fine for her to ask God for specific things she needs.  Liz describes a bizarre conversation she has in the car with this friend, where Liz actually writes a 'petition' to God in her notebook, asking him to get her husband to sign the divorce papers.  The very painful process of separating from each other has dragged on for eighteen months by this point, and if the papers are not signed they will have to go to court, which will take another year and involve very public recriminations, not to mention the expense.  So Liz writes her petition, signs it, and she and her friend list all their friends and acquaintances, and imagine them signing the petition.  Then they imagine all the famous people who would sign the petition too.  Finally, greatly cheered up, Liz falls asleep in the car (her friend is driving).  Shortly after she wakes up, her phone rings, and it is her lawyer calling to tell her that her husband has just signed.

Doubtless some people would have issues with the idea of praying to God to help end a marriage.  I sympathise, but I think it's important to realise that, during this time, Liz is clearly suffering from severe depression, fantasising about ending her life and refusing medication (which seems to her like a weakness - another stupid idea she has picked up!).  Whatever the rights and wrongs of her divorce, and her husband is clearly hurting a great deal too, the marriage is very much over by this point, and it's simply a question of how painful the ending will be.   

I wonder if there is a balance to be struck between praying for specific things and asking God to give us strength to cope with whatever happens.  While I believe God definitely does answer specific prayers at times, clearly there are many desperate situations which carry on being desperate, despite our prayers.  I absolutely do not believe, however, that God intentionally lets us go through tough times in order to teach us things.  He is not a sadist; he is a loving parent.  I don't think any loving parent has ever let their child run around with scissors, waiting for them to fall and cut themselves so that they will 'learn a lesson'.  Instead he suffers our trials with us, perhaps using these trials to teach us after the fact, but never willing us harm.