Barry Allen AKA the Flash is one of the more optimistic DC heroes. Barry has been through a lot in his life. But he somehow always pulls through and keeps going with a smile on his face. His TV show The Flash reflects that and contains more humor than other superhero shows like Arrow or Titans.
However, that doesn't mean the show doesn't deal with serious topics, and it sometimes cuts deep, both emotionally and story-wise. The show's heroes often suffer, experience loss or heartbreak, or simply struggle in their lives for one reason or another - and not all of these reasons are connected to battling villains.
Losing A Child
The show doesn't avoid portraying heartbreak in many of its forms. It also showed how impactful it can be when parents lose their child. Nora West-Allen played a major part in the fifth season. She traveled back in time to get to know her dad. Nora had struggled to connect to the younger version of her mom Iris, but they worked things out in the end.
Both Barry and Iris grew attached to Nora. So when she got erased from existence, they didn't take it well at all and grieved for her.
Being Comfortable With One's Identity
This topic is most notably present in Caitlin Snow's storyline. After she gets her ice powers all of a sudden, courtesy of Barry's toying with time, Caitlin doesn't know how to cope. She's worried the evil side of her will take over. She tries to hurt her friends multiple times.
It takes a long time for Caitlin to bring the two parts of her personality together, to understand that she and Killer Frost are one. While few people have a superhero alter-ego, many can relate to what it's like to struggle when someone has no idea who they really are.
Abusive Family
Even though the show understandably puts emphasis on the main characters, some side characters also have an interesting backstory. One of them is Frankie Kane, also known as the villain Magenta.
It's true that Magenta is a clear villain, but the show reveals that Frankie was forced to live with abusive foster parents. Magenta was Frankie's key to survival in the difficult situation it was in. While the show didn't delve in deep, it still showed that an abusive parent can have a huge impact on children.
Losing A Parent
To say that Barry hasn't had the happiest life would be an understatement. His life changed forever when the Reverse-Flash murdered his mom Nora. Barry was unable to help his mom.
And even once he got his powers and went back in time, he failed to reverse her death. To make matters even worse, Barry's dad also died when Hunter Zolomon killed him - right in front of Barry.
Being Falsely Accused And Imprisoned
Like father, like son. In Barry's case, the similarity didn't always lead to positive things. Henry Allen ended up imprisoned for the murder of his wife Nora even though he didn't kill her. And Barry ended up imprisoned for the murder of Clifford DeVoe even though DeVoe wasn't actually dead.
Luckily for Barry, he spent much less time in prison than his dad did, but it still showed the system doesn't always work.
PTSD After An Attack
It would be easy to presume that Barry comes out of all the attacks he suffers unscathed. But the truth is he struggled with something similar to PTSD more than once.
For example, when Zoom and Barry first fought, Barry ended up paralyzed from the waist down. He eventually recovered, but the experience left him shaken and insecure. He had to put in a lot of work and deal with his experiences before he could be himself again.
Conflicts Between Friends
It might not seem like such a big deal, but conflicts between friends can easily turn ugly. And if unsolved, they fester like an open wound.
Barry and Cisco mostly get along great, but they hit a low point when Cisco learned that Barry was - indirectly - responsible for the death of his brother Dante, because of Barry's meddling with time. Needless to say, that put a wedge between the two friends.
Friends Die
Despite Barry's mostly optimistic nature, the show is full of losses. The Flash team loses multiple friends during their fight against evil. And considering how strong bonds between friends can be, it takes a heavy toll.
For example, H.R. Wells sacrifices his life to save Iris from Savitar. And Barry is devastated when Oliver Queen sacrifices himself to stop the Crisis on Infinite Earths.
And So Do Loved Ones
However, The Flash doesn't stop there. It also showed repeatedly how devastating it can be when somebody loses their partner. The most obvious example is Caitlin.
When she first loses Ronnie, she closes herself off from the rest of the world. Caitlin buries herself in her job, is serious and sad. When she reunites with Ronnie, they get married and are happy together. However, their happiness is short-lived as Ronnie dies again, this time for good.
Toxic Relationships
Finally, the show doesn't shy away from portraying toxic relationships. It does so once again with Caitlin. Just when it looks like Caitlin could find happiness and love again, it turns out that Jay Garrick is, in fact, the evil speedster known as Zoom - and his real name is Hunter Zolomon.
That means their entire relationship was based on a lie. And Zoom even kidnaps Caitlin at one point, which takes their relationship from toxic to criminal.