You know you don’t like someone when you always refer to them by their full name. Instead of “Rob is such a jerk”, you instead say, “Rob Smith is such a jerk”.
It is as if you need more syllables to express your distaste for that person.
But to truly loathe someone is to always call them by their full name while making up a middle name that is a verb in the gerund tense such as “Rob Weedwhacking Smith is such a jerk” or “Rob Bellyaching Smith is such a jerk” or even the vulgar “Rob Mothermucking Smith is such a jerk.”
Of course, to take it to the next level is to add a “that son of a bitch” before their first name. Or if the object of scorn is a woman, “that daughter of a bitch Roberta Fingerlicking Smith”.
One or two Goddamns are always good to throw in there liberally as well.