There are many series, movies or books that I consider great and might have some influence on my persona but there isn't really one that'd define me or be a reason for some dramatic change in my life.
I'll give you some examples nontheless:
- After watching NGE + EoE for the second time I had an anxiety/depression period that lasted for a couple of weeks
- Ender's cycle by Orson Scott Card made me want to be an anthropologist and since I'll be starting my PhD next year, I guess that counts as certain level of influence
- Lately I got hit by an anxiety train hard after reading doki doki literature club but I got over it relatively quickly
- aaaand there are couple more that got strong emotional response out of me/fucked me over: Ef - a tale of memories and Ef - a tale of melodies, TTGL, Code Geass, Godfather, Oldboy, Phantom - Requiem for a phantom, certain episodes of Black Mirror and few more I cbf to list atm