Praying with Grateful Heart

I've always wondered and thought about my prayer life. I pray most often in the car -- that happens when you drive 80 miles a day to work. Are prayers still effective when you have the intent to pray before you fall asleep, but instead you being praying and fall asleep in the middle? I know God knows our hearts, but does He ever look down on us and say "Really? You can't even stay awake to talk to me?"

Now, in all fairness I have had company staying over when I fell asleep talking to them.... so when I do it to God, it's like doing it to a friend... right? The other night, it was 10:00 and I was ready for bed, done my routine, etc. My head had just hit the pillow and I began talking to God about various things. Today God gave me great hope about His answers to those prayers. I don't know what He has in store, but it's going to be great whatever it is!