During the episode "Attack From Space" the Herculoides while on the planet Luvanuum try to find a way into Zaygot's lair without alerting him and his henchmen to their presence. So Zandor asks Igoo to open one of the doors (as quietly as possible). And surprisingly enough, Igoo does just that and politely beckons the others in. Only for the doors to slam shut on his out-stretched hand! So what does Igoo do next? He proceeds to scream, then punch the doors until they're completely smashed. And what does Zandor have to say about all this you ask?
Zandor: (frustrated whisper) I said quietly.