Jökull is described by most as egotistical. He likes to go on about how perfect he is on a regular basis. It is hard to have a conversation with him without him telling you how you could never be him. Most people see this as annoying, which is why most don't like him. The Council can admit he is smart though, which is why they keep him on. Most of them also agree that he isn't as annoying as Hibiki. He doesn't really "make fun of people" per say, he just points out how he's better. No one really talks to him unless they have to or if he's just around. But he loves to talk. So if people don't seek him out he'll seek them out instead. Jökull is also intensely emotional—he'll be sobbing in a puddle of tears one second and throwing a chair and screaming the next. While he expresses most of his negative emotions behind closed doors, that doesn't mean people won't occasionally be caught in his fire. It's also important to note that Jökull is horrible at picking up on other people's feelings. 

Jökull is one to travel around pretty consistently so it's hard to catch him when you need him. He's always out to find someone to annoy with his long rants about nothing. Other than that he's out finding loopholes to sneak alcohol (called "shine" in the ghost universe) into the Council since none of them are actually allowed to drink per the rules of The Divine.