Moomin is pining for Snufkin...

If you want an example of Moomin and Snufkin's very deep feelings for each other, watch this movie:
http://www.muft.tv/watch/Video,Item,1655517014.html
(Moomin season 1 episode 24)

Short recap (Spoiler warning):
Moomin is having a bad cold and is pining for Snufkin, who hasn't come back to Moomin Valley although it's spring already. Everybody is worried about Moomin and wondering what has happened to Snufkin, who always before has turned up at the first day of spring. Nobody knows that Snufkin has also had a horrible cold and is slowly, due to his weakness, making his way back to the Valley where Moomin can't take it nomore and decides to go and look for Snufkin, despite being so sick...