[The Saucepan Man]

perhaps you're referring to the same type of vandals that later entered the Shire, and helped do Sharkey's bidding

Buttebur might not have been the most stout-hearted of fellows, but I hardly think that ruffians of this type would "freeze his heart". Doubtless they would daunt him, but it seems to me that Aragorn's words are implying something a little more out of the ordinary (for Bree folk, that is). Trolls, Wargs, and possibly Orcs, fit the bill for me.