Just how stupid was Ar-Pharazon?

Hi, Im new to these forums although Ive been lurking for a while and Ive finally registered. Anyway Ive been wondering something-When Ar-Pharazon invaded Aman what did he really expect to happen? That he could stroll in, kill or enslave all the elves (considering that the army of the Numenoreans was strong enough) while the Valar just sat back and watched? I know he was paraniod of death and Sauron had been persuading him. But surely he could see no matter how blinded that if he went in there that he was going to get a mountain collapsed on him or something of that sort. Id like to hear you guys thoughts on this.

P.S. Ar-Pharazon and most of the Numenoreans would have known the history of the First Age and who Morgoth and Sauron were. (And also know that Morgoth and Saruon had a nasty habit of killing men.) So why did he even listen to him and worship Morgoth in the first place? (Saurons mind tricks aside.)