oyasumi punpun. or if you want lolis and something that's slightly less depressing, dead dead demons dededestruction by the same author (inio asano). off the top of my head, i can't really think of any anime that felt really earth shattering or even deep and cool and interesting. aside from like evangelion (even though it's not my thing anymore), though i'm pretty sure everyone here has seen that. oh, actually i just remembered the original fma anime. that one's really good. it's very deep and interesting, really great worldbuilding too. it puts fmab to shame imo. you could also try cat soup, which is a short little trippy movie that is more than it may seem at surface level. and higurashi, though it's been so long since i've seen that and i'm not sure how well it would fit with what you seem to be looking for.