It's hard not to have certain expectations when the title of a story refers to a character as "happy." We're thinking we're about to meet a jolly, well-to-do, loveable dude named Francis. Maybe Frank for short.
But when we meet Francis, he is not happy at all. Right from the opening lines, and all the way through to the end of the story, a feeling of doom and depression prevails instead:
It was now lunch time and they were all sitting under the double green fly of the dining tent pretending that nothing had happened. (1.1)
There you have it, folks. Things aren't going well, and they are all in denial. Or at least they are trying their hardest to be. It's not till a few lines later that we find out why: Macomber has recently proven himself to be a coward. His failure, and then his various responses to it – guilt, resentment, humiliation – set the tone for the story. The upbeat moments should be read carefully, then, since they are often infused with deep and biting irony. When a character laughs, he or she just might be sneering.
He signals to the reader that things are not going to be straightforward right from the beginning: "Francis Macomber had, half an hour before, been carried to his tent from the edge of the camp in triumph on the arms and shoulders of the cook, the personal boys, the skinner and the porters" (1.11). But we already know that they are all trying to pretend it didn't happen, so that celebration can't have been genuine.
In fact, hardly anyone seems all that genuine in the story. Hemingway throws all kinds of sarcasm our way, particularly with Margot's dialogue. You only need to spend about a page with Margot to know that when she says "marvelous" she means just the opposite. Her remarks are about as sincere as Wilson's concession at the story's end about the shooting: "Of course it's an accident" (4.53).
So consider this a warning, Shmoopers: take everything you read with a grain of salt. These characters just might be trying to pull a fast one.