In which case, I'll alter my Willis recommendation to include her excellent and award-winning
Doomsday Book. While it is kind of dark and despairing at times, what with the plague and all, its basic themes are about humanity and hope and the care we take for each other. Wonderful stuff.
I'll also add in Steven Brust's somewhat irreverent Vlad Taltos series, about a human assassin succeeding in a world dominated by the non-human Dragaerans. Up until about
Teckla, it's pretty light in mood, despite the protagonist's profession. However, it's done in first-person narration from a fairly sarcastic point of view, so the style might not quite mesh with you. And of course, killing people for a living.
Robert J. Sawyer does some very hopeful science fiction novels. He's a fellow Canadian and has a fairly positive view of humanity and technology overall, despite any bumpy bits we may encounter in the road towards PROGRESS. If you like social-consequences sf that's a bit on the hard science side and especially stuff with dinosaurs and neanderthals (Sawyer studied to be a paleontologist, once upon a time), try some of his short stories,
available free on his website. But probably avoid starting with
Just Like Old Times,
Iterations, or even the award-winning
The Hand You're Dealt, which are a bit on the bleaker side for him.
For well-written mysteries that are overall positive despite the murders and such, and emphasize things like finding happiness amidst sorrow, both Barbara Hambly and Sharyn McCrumb do fairly good jobs.
Hambly is a well-established fantasy author who now also writes historical amateur sleuth mysteries. She's got two series: Benjamin January, an ex-slave trained as a surgeon and musician who tries to practice both his professions amidst the rigidly stratified racial/social conditions of antebellum New Orleans, in between solving murders. This one is very good and very popular, to the point where after the first publisher dropped it, another one picked it back up.
And using the pseudonym surname Hamilton, she also writes a new series with First Lady Abigail Adams as the amateur detective in pre-Revolutionary colonial US times. This one's a little lighter than the January series, due to Adams being more privileged and not having to deal so much with prejudice. But the January books are broader and richer and overall better, in my opinion, though they're both good reads.
Sharyn McCrumb is best known for her acclaimed Ballad novels exploring Appalachian myths and heritage, which are taught in several universities. She also has two mystery series which she doesn't seem to write any more, but have been released in e-book: The Elizabeth MacPherson mysteries, starring a forensic anthropologist, which I'm just beginning to read, having splurged on the lot during a recent Kobo promotion, and the Jay Omega mysteries, which are a tremendous amount of fun and explore science fiction fandom. Sadly, only
Bimbos of the Death Sun is available from that.
Oh, and if you like fairly upbeat adventure mysteries (not so much with the careful deductive sleuthing as just following the breadcrumb trail of clues), you might like Suzanne Arruda's Jade del Cameron mysteries, set in colonial Kenya back in the 1920s back when it was still just British East Africa. A bit of a retro-pulpy Indiana Jones-type feel, but doesn't shy away from the more serious surrounding issues of the times while not dragging you down into it. Author puts up
helpful historical notes on her blog, too, if that's something that might interest you.