In the Christmas special "Snow Business", there are some huge heartwarming moments:
Norman ringing the fire brigade to help Sarah and James out of the ice. Considering that the three don't always have the best of relationships, it is touching to see Norman do some good for once.
James: Are you sure you told them where we are?
Norman: Yes! Of course I did!
Sam handing out presents to Sarah and James by the village Christmas tree, while Norman looks on dispiritedly. Not only is his mother embarrassingly tipsy, but it seems he has no father or uncle figure in his life, and it may be that he envies the twins for having Sam. However, Sam unexpectedly pulls another present from the sack and gives it to Norman, who is amazed and delighted. It's even more heartwarming because, despite Norman's generally bad behaviour, he really does deserve this reward after helping to rescue the twins earlier in the episode.
Sam: Here you are, Norman. There's one for you, too!
Norman: Aww, thanks a million, Fireman Sam!
The ending, where Sam hangs a stocking over his mantelpiece and, since he will be on duty on Christmas Day, wonders whether or not he's too old for Christmas. This combines with a TearJerker along with a slow Christmas version of the theme.
Sam: Might as well hang this up, just in case. Don't suppose he'd call on me, though. I'm a bit old now. Oh, I don't know...you're as young as you feel! Happy Christmas, Pontypandy!