Some of mine are:

Durarara - this site of course!

Planetes & Twin Spica - Taught me about Space Junk! While I wish Twin Spica was longer, I still really enjoyed the ride.

Hikaru no Go & Piano no Mori - inspired me to be more persistent towards my goals and to appreciate how far I've come when it comes to my interests (as well as work to get even better)

Kemono no Souja Erin - impacted my career choice (in a way that's not immediately obvious)

Nodame Cantabile - got me into classical music

Haikyuu - got me to exercise lol

Looking forward to reading your guys' replies!

Slam Dunk and kuroko=im a neet so i surprised it made me go outside and awkwardly play basketball outside with strangers....motivation only lasted a day. never go outside ever after that hahahaa....

oregairu- not impacted, more like i relate to hikagaya...i also want something genuine

code geass= made me like bad endings where mc dies.....made me like stuff like akame ga kill ending.

Inuyasha me hizo cantar
Sakura card captor me hizo dibujar
El detective conan me hizo amar la resolucion de acertijos
Death note la profundizo
Senyuu me hizo reir en mi peor momento
Magi me dio imaginacion
Soul eater me hizo amar el rock
kimi ni todoke me hizo entender mis sentimientos romanticos
Y durarara me dio este chat en mi juventud para tener amistades de juego, pero fue entretenido en su epoca uwu

>>3 Hermano.

maybe a little TMi.

DuRaRaRa. Caught a random episode on Adult Swim, and at first I thought little of it. It started growing on me, and somehow led me to find this site and the chat rooms.

I didn't know how much I needed what the series gave me, and I'll always remember it for the awesome time I had; being part of this community, the fanbase and the works. It gave me relief from my daily life of long-term Depression, even if just temporarily. I don't think I've ever really experienced this kind of community before then, and I learned a lot. Helped me find some new fun hobbies; and surprisingly met many chill people, at a time when I was getting more asocial [and maybe even misanthropic] everyday.

TL;DR: it helped me cope, always a win. It gave me an adventure I'll never forget, even though it wasn't perfect.