Probably a classic like El Hazard or something fun. If I'm down and feeling empty, I usually try not to compound it with more sad. XD
I don't rewatch a lot of stuff but I love to re-read Bakuman as it is my favorite manga of all time.
It never gets boring no matter how many times I read because it is so well written that I end up cheering on the characters every single time.
I watch stuff like bokurawa minna kawaisou, d-frag, or gekkan shoujo nozaki-kun, when I want something light. Else it's always death note, AOT
Whenever im really sad or depressed the best way to cheer me on is by putting on "kai watching clannad for the 80th time like something changed from the first 79 times"
I feel like I'm too happy to ever empty...
only bored asf but I don't rewatch that much cause even my 9+ ratings are in the top100 atleast...
still some of my absolute fav...
Higurashi series (just for the crinch and chills UwU)
Nichijou, OPM, Baka test, Kore wa Zombie (just because I love Comedy) there are even more... but dats gonna be too much xD
sth to cry?... Anohana, Clannad, Canon (I swear to god the first time I watch it i was like... kinda feels like clannad xDD)
Overlord, the voice acting for that show just fills me with joy
a silent voice ( i have seen it 17 times now ) it is quite sad though
It depends off how I feel but I'd normally re-watch: Fullmetal Alchemist Brotherhood, Sekaiichi-Hatsukoi, Code Geass, Your name or if it's August (well EVERY August) I re-watch Summer Wars.
I kinda want to have selected amnesia where I forget an anime I love ...and rewatch and reride that feels train...