You're taking this out of context and misapplying it.

(Mark 11:22-24 NIV) "Have faith in God," Jesus answered. {23} "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. {24} Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours.

Jesus was talking to the disciples. He was talking about getting whatever they needed for their earthly ministries. It wasn't meant to be a way to get whatever you want in life. EVERYTHING you pray for is subject to the will of God.

I prayed for my unborn son. He was stillborn. I prayed for my unborn daughter. She was stillborn. I prayed for the life of my wife. She died from kidney disease when she was 30. So don't you dare tell me that I can whatever I ask for if I have enough faith. Life doesn't work that way.