Fred Astaire - I'm Building Up to an Awful Letdown lyrics

I'm like Humpty Dumpty, Up on the garden wall, I'm riding high, And who can deny That whatever goes up must fall. Poor old Humpty Dumpty, He got the toughest break, And yet his fall Was nothing at all Like the tumble I'm gonna take! I'm building up to an awful letdown By playing around with you. You're breaking down my terrific buildup By treating me as you do. My castles in the air, My smile so debonair, My one big love affair, Is just a flash; Will it go smash Like the nineteen twenty nine market crash? I'm building up to an awful letdown By falling in love with you.