I've seen this movie several times, and for some reason the littlest gestures in two scenes were the sweetest to me:
When Adam walks her home (after her little brother falls asleep & doesn't pick her up), and he protectively shields her with his arm from the passing snowplow.
When they're sitting on the porch swing kissing on New Year's Eve - his arms are around her, and he gently pulls her coat closed in front to keep her warm.
Too many to choose from, but the most memorable scene for me is when he stole the Christmas tree and put it up in Caroline's room. I wish I had a man to do something like that for me.
I have many favorite parts, but I especially love it when Adam says, "....Whenever my life doesn't agree with me, I lay down and listen to these records and the rain stops falling."
Music often helps me when my life doesn't agree with me.