Kaizaki Arata's a struggling 27 year old NEET who can't find a job.
And by chance he runs into a guy who gives him the chance to turn his life around.
That's the short version of it.

How does this anime reflect real life issues?

-Chizuru Hishiro has always struggled to make friends.
-Growing up, Chizuru moved from school to school, so it was hard to keep any friends.
-One of Kaizaki's mentors in his old job is bullied and picked on because of jealous co-workers.
-Another character from ReLife struggles with the insecurity of being "2nd best".

And there are deeper elements baked into this anime series.
https://i.imgur.com/WNKtDng.png

Black Lagoon follows the lives of independent criminals. Also known as: The Lagoon Company.

What's so realistic about this anime?

-Smuggling drugs and weapons in and out of countries, towns and cities.
-Shoot outs and gun crime is also a real thing in Black Lagoon. Again, a real issue in our society.
-Gritty towns and cities that seem "lawless". Though uncommon in the real world, it is a real thing.
-Being a victim of rape, and never reporting it to anyone.This is a deep issue in our society.
-People who grow up in dangerous neighborhoods with few opportunities.

While the "action" in Black Lagoon may be flashy and dramatic, under the surface it's a realistic series.
And these types of issues are rampant in specific parts of the world.
https://i.imgur.com/BpU8MWL.png

Hell Girl is a horror series with a similar theme to the anime: Death Note.

Here's how Hell Girl reflects real life problems

-A sadistic woman spreading false rumors around your neighborhood to tarnish your reputation.
-Kids bullying you, and using you as a "bank" to take money with a false promise of paying it back.
-Abusing pets, and leaving them for dead.
-Jealous people accusing you of cheating on your wife or husband.

These are a handful of dark themes running throughout Hell Girl from start to finish.
As awful as it is, these things DO happen. Even if it's uncommon.
And in some cases, it's irreversible and can ruin your reputation for a lifetime if taken too far.
https://i.imgur.com/JsxlsSR.png

A horror/psychological anime series filled with sadness, immorality, and strong themes.

Reasons why this anime reflects real life

-Child abuse. Yes, this is a real and horrible thing that's show in Elfen Lied.
-Running away from home. This is a result of the last point.
-Abuse towards animals. Again, this is horrible and wicked down to the core.
-Some people are born into cruel circumstances, for no fault of their own.

Despite the immense gore and colorful language in Elfen Lied, the underlying theme is authentic.https://i.imgur.com/IyijDjD.png

The main theme is all in the title. But besides that

-Bullying is also a highlight of Haganai.
-The awkwardness of making friends, meeting new people and loneliness.
-Being mis-judged based on how you look, and how you deal with that personally.

There's also a couple more meaningful elements expressed throughout Haganai.
And that's what makes this school/slice of life series stand out among others.
https://i.imgur.com/m72VHju.png