In Defense of Kylo Ren

Anger Issues

Ok. This is a big one. Kylo Ren has a comically short temper and snaps a band several times in "The Force Awakens." Despite the fact that the viewing audience gets a few laughs out of it, in universe, his rage is terrifying.

The first instance is the First Order officer towards the end of the first act who informs Kylo of the escape of BB-8 and that he had help from Finn. He looks afraid to talk to Kylo from the beginning knowing he will be angry. He also treats him with the utmost respect, removing his hat before giving him the bad news. As Kylo pulls his weapon from his belt, and ignites it, the officer seems certain he will be cleaved in half, and is surprised when Ren focuses his assault on the console in front of him. The man is shakey, and unnerved by the very idea of giving Ren bad news.

Later in the film, Rey utilizes a Mind Trick to escape her imprisonment on Starkiller Base. Once Kylo returns to the cell where she was being held, Ren again lashes out, destroying the restraints that held Rey and slashing the room. Two Stormtroopers walk by the carnage and get away when they realize how furious Kylo is.
Again, if he was as pathetic and childish as people say he was, why would the Stormtroopers run away if they weren't legitimately afraid of facing him.

Kylo's rage is also easily explained by his conflict. It is established that he is caught in the balance between the Light and Dark side, and desperately wants to be cemented in the ladder. As we know, rage and anger are emotions that embrace and fuel the Dark Side, so it would make sense that an individual who is trying to give himself to the darkness would intentionally throw self control out of the window. That being said his rage most likely saved his life. Even with Jedi, giving into anger often leads to the Force granting heightened physical abilities  (Anakin and Luke's superhuman strength we see when they were pressed often came from this), Kylo was able to give himself to anger and adrenaline to power thru a bowcaster blast, then engage in two duels and survive further injuries simply by coasting off of his rage.

Uncontrolled rage has also been a defining trait of other popular and more respected Dark Siders. In fact, Kylo Ren's surrender to the darkness mirrors another popular character: Darth Malgus. Malgus was a Sith Lord who (like Darth Vader) used the power of his anger and hate to survive a traumatic injury. But that rage came to be from his killing of his lover Aleena. Sound familiar? He was held back by glimmers of his old life and his compassion so he killed a symbol of that compassion and past self to try to purge the light? Though it didn't work for Ren, he tried the same methods, and his rage sustained him and despite how humorous the audience found it, he was feared both by those who served him and those who stood against him .