In anime, staying at home apparently makes your life more interesting.
Hikikomori is a phenomenon where a young person becomes a shut-in, cutting themselves from any social interaction for a prolonged period of time. These people are usually NEETs — not in education, employment, or training. Despite that, they can make for good anime protagonists — here are some examples.
Welcome to the N.H.K. (Crunchyroll)
Perhaps the most famous anime with a shut-in protagonist is Welcome to the N.H.K. (NHK ni Youkoso!). Satou spent 4 years as a shut-in, slowly becoming obsessed with his own delusions and conspiracy theories.
After suddenly meeting Misaki Nakahara, though, he decides to change his life. Perhaps the most interesting part about the anime is that it is actually based on a semi-autobiographical novel.
WataMote (HIDIVE)
If Welcome to the N.H.K. tries to be the realistic take on hikikomori life and redemption, then WataMote: No Matter How I Look At It, It's You Guys' Fault I'm Not Popular! (Watashi ga Motenai no wa Dou Kangaetemo Omaera ga Warui!) is the exaggerated cringe comedy version of it. It’s very hard to watch at times, but that’s what makes it so good.
Tomoko Kuroki is extremely antisocial, and her high school debut is a total failure. Of course, she puts the blame on others. She gets better, although it takes a long time.
The Vexations of a Shut-In Vampire Princess (HIDIVE)
Another anime with a female shut-in protagonist, The Vexations of a Shut-In Vampire Princess (Hikikomari Kyuuketsuki no Monmon) follows Terakomari Gandesblood as she is put in charge of an army of delinquents in a world where conflicts are solved by mock-up wars.
Terakomari hates drinking blood and wants to be a writer. She hates interacting with people, but every time she does something, people misinterpret it as a genius move, adding to the comedy.
ReLIFE (Crunchyroll)
ReLIFE gives a NEET protagonist, Arata Kaizaki, a chance to redo his life. Arata is then reverted to the age of 17, and now has to attend high school.
The romantic drama arises from there, but he also has to deal with the change in school policies and rules — as well as with having to actually study again.
ChäoS;HEAd (Crunchyroll)
ChäoS;HEAd is set in the same universe as Steins;Gate, but is mostly standalone. While it is not a very good adaptation of its visual novel, it does one thing very well.
Takumi Nishijou, the protagonist, is a shut-in that barely attends high school. He suffers from constant delusions and can’t tell what is real and what is in his head a lot of the time, which adds an extra layer of mystery to the anime.