Looking farther back in Barryās life pre-season 1 requires a lot of speculation bc of the limited canon information but this is my take on it.
Since Barry has always been aware that he was adopted that permanently damaged his sense of self worth, and for reasons unknown seemed to have internalized a constant desire to seek power and success, and a low tolerance for people he perceived as below himself (this could be caused by something specific or could just be the general privelege and conditioning that happens with cis white men). This combined began his anti social tendencies, isolating him from others outside a professional sense and causing him to seek what he wants without taking no for an answer while also being prepared to destroy anything that doesnāt turn out in his favor (cough not leaving Lana alone/the bomb he clearly had previously planted under Frambiose's car just in case cough). It also doesnāt seem like he had any friends at Odin, he was Trexlers second hand man because of results and people pleasing since he didnt seem to be liked as a person by even Trexler himself. He was a great employee but if you spent too much time with him outside of that he was odd in a bad way that drove people away.
His relationship with Frambiouse is also notable because she clearly has a habit of sleeping around the office and I suspect thats how thier relationship started. And like the fling with Lana he saw an opportunity one time and insisted upon it from that point on. Which in this case turned into an established relationship but most likely a low maintanence one where the reality is he wanted sex and loyalty without having to put in too much effort. Which would explain why he is a huge hypocrite in that whole situation as he was clearly flirting with Lana despite being in a relationship with Frambouise yet got so enraged by her cheating she lost her job and almost died.
And the kicker of it all i don't think pre-cyborg Barry even thought of himself as a particularly bad person. A petty and stubborn one sure but see himself as the villain? Nope.
He got away with so much for so long mainly because men tend to get away with serious red flags and violence was in his case an occupational requirement. Many such cases!
