Yes, that's definitely a part of it. My anger is fueled by deep feelings of betrayal, of having been lied to, set up for a fall. Robbed. Cheated. It feels like I have been knocked down, kicked, and my face ground in ****. It feels like my very heart and soul have been defiled. It's the exact same feeling with both jobs and dating.
I don't mean to be arrogant and I'm sorry if that is graphic or extreme, but upward mobility has always been very close to my heart. The idea that I am strong enough and smart enough to get there, that I am every bit as good as the other guys, that I'm a threat to them, that I can make what I want happen. It's very important to me to be able to reach something good in this world and hold on. I've always dreamed of that, having a house (doesn't have to be a mansion, a small house would be fine as long as it's just me, but I would have to own, not rent), a nice car, getting good at the things that I am interested in (legitimately good, not a hobbyist), being free to follow my interests, and of course, dating someone that I want.
Without those, I simply can have no pride. And without pride, I can't feel good about myself. It would crush my hope, my will to go on. The good feelings in me would starve and only the bad feelings would be left. I'd pretty much be dead inside.