Recommend a tear jerker.
Say what? Hm, I am not much on tear jerkers unless they are Bollywood films. I don't like stories with a lot of tragedy, since these days it seems like there is quite enough tragedy to deal with in real life. I don't need extra. (Bollywood films don't count, because they are so over the top about it.)
Aha! I know! Connie Willis' time-travel saga, Doomsday Book. I've only read it once because it's so darn sad. It's a great book! And the sequel, To Say Nothing of the Dog, is clever and hilarious, so I've read that several times. It's a great cheering-up book. Ahem. Doomsday Book--the publisher's summary:
For Kivrin, preparing an on-site study of one of the deadliest eras in humanity's history was as simple as receiving inoculations against the diseases of the fourteenth century and inventing an alibi for a woman traveling alone. For her instructors in the twenty-first century, it meant painstaking calculations and careful monitoring of the rendezvous location where Kivrin would be received.Kivrin accidentally arrives in the Black Plague, and meanwhile back in her own time, a new strain of influenza strikes down half of the people who are supposed to be monitoring her. It's a great story, and it's really really really sad.
But a crisis strangely linking past and future strands Kivrin in a bygone age as her fellows try desperately to rescue her. In a time of superstition and fear, Kivrin -- barely of age herself -- finds she has become an unlikely angel of hope during one of history's darkest hours.
Edit after the fact: I didn't look carefully enough. This is actually the prompt for Day 5, not 4. Oops. So, I'll do 4 tomorrow.