Lovable Fools: Arthur Hastings

"Fool" does, to an extent, depend on the definition. As defined on Votaries, the fool can sometimes be very wise. Overall, the fool seems to have a deep capacity for trust, which makes the fool unfortunately vulnerable to hucksters and manipulators.

Agatha Christie's Poirot is paired to the clueless Arthur Hastings in the early short stories and novels. Although the clueless sidekick is a trope of mysteries, Hastings--even by mystery standards--has always been considered remarkably dumb. (Archie Goodwin is considered by many to be the best of the sidekicks, being a detective in his own right; both Archie and Nero hold detective licenses through the State of New York.) Christie eventually dropped Hastings though he shows up in Poirot's final novel (written years earlier).

In the BBC series, Hugh Fraser as Hastings not only has hobbies (cars, photography) and the quiet habit of correcting Poirot's English (exchanges decided on by Suchet and Fraser) and fantastic clothes but the same gentle nature that graces the character in the book.

Hastings, for instance, doesn't suspect his wife-to-be, Bella, of being a possible murderer. In the book, she is a twin and not involved. But she is a legitimate suspect. The movie combines the sisters--and Hastings still has no idea. But the movie brings home the "fool" aspect of Hastings as refined above. Bella chooses Hastings at the end since she would rather be with a good man who doesn't suspect deceit than a man (her prior lover) who is constantly waffling and suffering because he is forever plunging himself into ethical quagmires and pulling other people in as well. 

The same quality that makes the fool vulnerable makes him lovable.