One thing I'm really into is Mobile Suit Gundam, in particular the 1985 sequel to the original series: Mobile Suit Zeta Gundam. It means a lot to me.
The 1979 anime Mobile Suit Gundam is an anime that takes place in the indeterminate future, where humanity has colonised the space around the Earth sphere. It chronicles the desperate battles between the Earth Federation and the space colonies of the Principality of Zeon, with a strong focus on the self-destructive nature of war. The two parties had recently come upon the technology to make space combat more efficient and deadly: mechs, called Mobile Suits in-series.
The story itself centers on situationally-conscripted teen Federation mobile suit pilot Amuro Ray and his fight for survival, and parallel to that the revenge plot of Zeonic pilot Char Aznable, his combat nemesis. As Amuro Ray struggles to protect the civilians and mostly-civilian crew aboard the White Base, Char finds that he now has a stumbling block on his rise up the ranks in the form of the Federation's terrifying new weapon, the Gundam, piloted by Amuro.
The story as it is presented is emotionally gripping and tragic, much unlike the later additions to the Gundam franchise such as G Gundam and Gundam Wing. I first saw it in summer of 2015, and have been hooked since.
The 1985 entry to the Gundam series, direct sequel to 0079, is Mobile Suit Zeta Gundam. It takes place 7 or 8 years after the end of the One Year War, the events of 0079. Its focus is no longer on Federation vs. Zeon - instead, the Federation has grown tyrannical in its pursuit of Zeonic remnants, and a faction called the Anti-Earth Union Group has taken up arms to combat their terrible treatment of space colonies and their inhabitants.
The main character of Zeta is an older teen named Kamille Bidan, who I've written about. He is an impulsive and reckless kid, and his actions lead to him coming into contact with the AEUG and on-the-spot joining their pursuit against Federation special force, the Titans. In my eyes, the story has two main branches - the political backdrop of the Titans vs AEUG conflict, and the twisted and gnarled growth of Kamille Bidan as a person under the adults who take him under their wing. Characters such as Amuro Ray and Char Aznable return in Zeta, and everyone's relationship has since changed post-war.
Zeta ends catastrophically, and was hard for me to watch. I saw it late summer 2015, and identified strongly with Kamille Bidan, who is now my namesake. His story continued in ZZ Gundam, but the parts contained in Zeta were thoroughly heartbreaking.