Balfrog, I agree with you that the scene with the trolls is '
a comic masterpiece'; because Tolkien still made them very dangerous despite them being 'thick'. While their stupidity was obvious, and was later exploited by Gandalf to ensure they turned into stone, Tolkien made it clear that once anyone got into their clutches, that person would later end up in their stomachs...
If Gandalf hadn't been there...