I prayed...therefore God exists?

Whenever I promise to pray for someone--maybe they have a family problem or illness--I pray to the Living God, the Creator of the universe (His Son is Jesus, the Redeemer). I don't need extra time to sort out whether God's listening or engaged...whether He's out there. In fact, I thought that was kind of self-evident...if I'm praying to Him, I must believe that He exists.
But I'm learning that's not always the case when people say "I prayed to god that wouldn't happen," or "I offered up a prayer right then and there."
There's an interesting verse in the Bible's New Testament--Paul's letter to the Hebrews, Chapter 11:
"And without faith it is impossible to please God, because anyone who comes to him must believe that he exists..."
Randomly directed prayers to the universe--or even focused prayers directed with laser intensity to "my higher power"--aren't going to get anywhere, or accomplish anything, if we aren't ready to acknowledge and place faith in the existence of God.

Jesus had a conversation with a man after he healed him of blindness:
JN 9:35 Jesus heard that they had thrown him out, and when he found him, he said, "Do you believe in the Son of Man?"
JN 9:36 "Who is he, sir?" the man asked. "Tell me so that I may believe in him."
JN 9:37 Jesus said, "You have now seen him; in fact, he is the one speaking with you."
JN 9:38 Then the man said, "Lord, I believe," and he worshiped him.
Then the man said...Lord, I believe.

What do you believe?

Oh...my...God!

We don't usually think of the 10 Commandments when we're listening to TV, movies or casual conversation at work. But how many times does someone say 'oh my God' or in combination with 'damn' or a more specific expletive of His Son's name without intending it for spiritual reverence--that's the definition of using it "in vain" - and going against God's specific third command. They go like this:

1. Have no other God's
2. Make no idols or images of other gods - or bow before them
3. Do not use God's name in vain [misuse it]
4. Keep the Sabbath day Holy [observe it]
5. Honor your mother and father
6. Do not murder
7. Do not commit adultery
8. Do not steal
9. Do not lie
10. Do not covet [long for] things that other people have that you don't

Few people in today's climate of diversity exhibit the sensitivity to exclude God's name from exploitation around those it offends -- namely the majority of people in the U.S. -- according to polls.
Would there be any outcry if we start casually cursing other prominent religious figures' names in our oaths?
Fill in the blank with a highly visible eastern or middle eastern religious name.... "Damn _______ ! "
No, I don't think that's appropriate either - so can we start taking God and his Son Jesus' names out of the scripted swearing and cursing lexicon of Hollywood and network TV?
Then maybe people who are not Bible believers could also speak up at restaurants and coffee shop conversations to say..."you might want to watch your language, you could offend someone who's spiritual diversity revere's the god you're casually cursing...."
Or substitute some other religious leader's name and check the reaction.

What do you believe?