I have a doubt but Niles mistreating C.C. not have wanted to express jealousy, maybe it was angry because he liked C.C. but she loved Maxwell and so has turned to abuse, nor think that.

are fans 100% of the couple Niles / C.C. but I also like very much Maxwell / Fran

Good theory. Maybe he did not stand her at first because she was kind of evil. I liked how they were at each other's throats during the last two seasons and he finally revealed that he was in love with her. LOL.

too funny their spat