Viserys Targaryen hates most people.
This includes his slut of a sister, his mad father, his weak mother, and his fool of a brother. Not to mention everyone last bloody whoremonger in Westeros who bowed to the Usurper and all of the Dothraki, besides (Viserys simply finds them disgusting).
But not Jorah Mormont. Well, most of the time, anyway.
"Most of the time", however, is more than Viserys is used to tolerating (oh seven hells, liking) someone for.
He likes the way that Mormont (Jorah, he calls him, but only at night before he falls into a fitful sleep in his tent) always asks him how he finds the Dothraki Sea today. Viserys may always respond with a remark such as yesterday's charming "The way I might find a poxy whore" but still, the gesture is appreciated.
He likes how Mormont (Jorah) tells him about his life on Bear Island before his exile; how he used to wield an axe and chase his sisters and even fish barehanded (barechested?)
He certainly doesn't like the regaling of Lynesse Hightower's (NOT Mormont's) sexual prowess, however. It seems she and Dany would've gotten on quite well.
He likes that Jorah doesn't bat an eyelash when he goes into one of his freezing fits, shaking and sobbing when no one else but the ex-knight is around (it's so, so cold and where is Mother and is Dany safe and is someone behind him?).
Jorah merely offers him another cup of wine and the option to sleep curled up to his bulk that Viserys always immediately declines.
Most of all, though, he likes the way the man calls him his King.