I think that if you read Plum, as P.G. Wodehouse's friends and readers call him, his words will give you many cheerful heart moments. I find that his world of silliness is a good one to enter. If you are feeling down, or even already cheerful, read a Plum novel for laughter. Good news is that he wrote about 90 novels.
"It is impossible to be unhappy while reading the adventures of Jeeves and Wooster. And I've tried." -- Christopher Buckley.
Wodehouse is known for his Jeeves and Wooster books, and Stephen Fry and Hugh Laurie did a brilliant job acting in the TV series "Jeeves and Wooster". So funny to me and to many.
Here are covers of some representative titles. My favorite Plum novel might be "The Code of the Woosters." I gave a copy to our minister when he left on a sabbatical; I have seen that being a minister is a very tough job and laughter can be applied as needed.
I find I can turn to any page in a Wodehouse book and find humor. Here is one random snippet from page 2 of My Man Jeeves. "After this," I (Wooster speaking to Jeeves) said, "not another step for me without your advice. From now on consider yourself the brains of the establishment."
"Very good, sir, I shall endeavor to give satisfaction."
And he has, by Jove! I'm a bit short on brain myself; the old bean would have appeared to have been constructed more for ornament than for use, don't you know; but give me five minutes to talk the thing over with Jeeves and I'm game to advise anyone about anything."
Another fabulously funny series is the Blandings Castle books featuring Lord Emsworth, not the brightest guy around, and his devotion to his prize winning pig, The Empress. See above photo, Uncle Fred in the Springtime, on the cover is the Empress taking a bath. Just the character names alone bring me smiles, uncle Fred is the Fifth Earl of Ickenham and he dependably drags his nephew Pongo Twistleton into trouble and somehow they survive.
Proverbs 17:22 reminds us that "A cheerful heart is good medicine".
Here is our esteemed author himself, living in the USA.