You might not know this, but most ghouls have never even met a vampire. And while creepy sorts with ghoulish outlooks like to serve those guys, ghouls themselves aren't into eating bugs. They're into meatier stuff than insects and worms-- You know, like arms and legs. Having died and clawed their way out of their coffins also tends to make them not very photogenic, so answering the door when UPS shows up for a sleeping Nosferatu is very rarely in their job description.
Ghouls are folks that have reawakened after death and know only one thing, human flesh is delicious. This can happen because a curse that someone else cast upon them before their deaths. It can be karma for horrible deeds done in life by them. For some individuals, it can be sort of a family inheritance, say a hold-over from when Great-Great Grandmother consorted with devils to win a beauty pageant.
As mentioned earlier, ghouls love human flesh. Not only do they like it, they need it. Eating corpses holds a ghoul together. The hungrier that one is, the more it decomposes. The fresher the flesh consumed, the more it does for them. When they are able to get sustenance from a living person, wounds heal and decomposition reverses, much of their living personality returns as well. Also as the body-eaters eat a corpse's brain he learns some of things that the meal knew in life. In Game terms, this means most ghouls have a whole lot of Perks.
Ghouls are hard to be around. Some sort of natural revulsion occurs when the still living sees one of the reawakened, no matter what kind of shape they are in. When the creature is almost human, every Character must make a Nerve Draw at 4. The hungrier it is, the more horrifying it becomes, so the GM should adjust the Draw likewise.