It’s A Place Further Than The Universe for me, both the first time and the first rewatch. Absolutely phenomenal series.
Also Violet Evergarden. Went from not caring about anime at all to a favorite pastime, and also rediscovering my emotions in the process.
I have a hard time imagining an anime really changing the way I live or think, but FMA:B and AoT were what really got me into anime so I guess those are as close as it gets.