Why do people raise their hands in church?

While at church this morning, Madison leaned over to me and asked "Mommy, why do people raise their hands in church?".  I told her that when people feel happy about Jesus and God, that they raise their hands.  Madison told me that I could raise my hand because church makes me happy.  I told her, yes church makes me very happy (but of course I could raise my hands b/c I was holding her).  I could tell that she was thinking about what I said.  While we were singing our praise and worship music, she raised her little hand while she sang.  It darn near broke my heart.  Tears were streaming down my face!  Madison didn't think anything about it b/c I often become very emotional during service and cry almost every time.  She knows that they are happy tears b/c Mommy loves church.  My dear, sweet Madison!  She is an AMAZING child!