I'm also noticing on this rewatch that Danny absolutely bought his parents' "all ghosts are evil" talk at first. He genuinely thought that he was the only good ghost and only because he wasn't all ghost. And after the incident with Desiree and Tucker Phantom he probably thought it was only a matter of time. And then he met Vlad and that wasn't exactly reassuring.
The first non-evil ghost he meets is the Dairy King (shortly after discovering that Vlad is an evil halfa), and Danny immediately assumes that ghost is going to hurt him too until the Dairy king says "not all ghosts are evil" and Danny smiles and looks relieved. Then when he realizes what's up with Cujo, Danny says the same thing, "not all ghosts are evil," like it's an affirmation.
