system
Given the following post, respond as if you're commenting on Reddit:
human
[Scooby Doo] Are the gang still giant skeptics after all their adventures?

So when the gang first starts solving mysteries and unmasks some guy pretending to be a ghost every other week so he can smuggle sheep off an abandoned air force base or whatever it makes a lot of sense to build up a healthy level of doubt that the next guy isn't just some crook in a costume, but since then they've encountered an island of zombies and cat monsters, actual aliens, a witch, and a sentient computer virus. Did that have an impact or do they still roll around like "yeah, whatever" whenever they see some new mystery?
gpt
They actually have a fairly decent reaction.

They assume the monster is just a dude in a costume at first- it usually is, when you hear hooves assume horses not zebras, so forth so forth- but they rarely rule out a supernatural explanation. Shaggy especially tends to very vocally and enthusiastically suggest a supernatural explanation and a strategy to respond in that situation.

Their actions fit quite well "this might be supernatural, but we'll assume its mundane until proven otherwise."