Glacier doesn’t like it when others come in and try to take over his daily tasks as he likes them the way they are.  
He doesn’t like sharing the work load nor does he like admitting that at times he does actually need an extra pair of hands.
 
I plan to have him and his princess, Princess Spiritus, to meet Spike and Twilight in their little story. As Glacier is the only other dragon that Spike know of working and living with a pony he becomes very attached to him, even though Glacier is not very found of having Spike around. The fact that he has been isolated from other dragons, Glacier has become too unsure about himself and how he should react with other dragons, including Spike. He also doesn’t like the idea of having a baby dragon around the place as it makes him feel responsible for him and is forced to “babysit” Spike.
 
More on Glacier; https://derpibooru.org/684707?scope=scpe230463bb577039d1e28ac6b622f2da6b75a1f8cd
 
About Princess Spiritus; https://derpibooru.org/658455?scope=scpe230463bb577039d1e28ac6b622f2da6b75a1f8cd