He was the calmest & most positive & most supportive Troll of us all ! - I guess those 'Keep Calm &...' messages might have been invented by him because he was just like this: calm & smiling, approaching everything with Zen like wisdom. 

He could always cheer you up or calm you down depending on the situation when he was near you. All the Trolls loved him because he was so kind & always knew what to say. And he had a nice voice so when he was singing - Everyone was listening. He always was the center of attention of other Trolls.

( If you watched the 'Trolls' movie - you obviously know why I say 'was' not 'is' here ).