Look, as much as Captain Hastings reminds me of a Labrador - good-natured, but not very bright - it does seem a bit off when his purported friend constructs a trap around his dimwittedness. I wonder, sometimes, if Poirot's popularity has maintained itself over the years because he's a bit mean as well as being a lot clever. It does make him entertaining, but if I'm honest, I think that as a friend he'd be simply unbearable.