Overall:
This is my kind of story. So, automatically I was likely to enjoy it, which I did, probably more than anything else I've read on here, but that's my personal taste more than anything.
Plot:
Could be wrong, but I'd guess you've been reading up on your Orwell. A lot of the aspects of the plot I could draw similarities from to 1984. Evan works in a cubicle. He's uncertain about his job and feels alienated in some ways. He finds refuge in a place which makes him feel free. The posters reminded of Big Brother. His coworker, Ted, conforms to the idea of not-questioning--a freedom in following. Anyway...
The plot wasn't bad. I think what you have works fine, although I do have some suggestions.
Some random things:
Quincy--why did he call Evan? It wasn't really explained. It just kind of happened. Nothing was really initiated by it, except maybe characterization of the boss, which felt forced.
Pacing--The transition from him being complacent to burning the posters is too quick. I'd recommend adding more arc to your character. The entire story he is basically the same person. He doesn't like the job; if you were to start with him being excited about it, then his change of behavior would be much more gratifying to the reader. This would, of course, cause you to add a few hundred words probably.
Characterization--Not bad. In a short story like this, you have to give an impression of the characters with only a few words. Ted is obedient. Evan is doubtful. Quincy is odd. Jen is friendly but distant. Chuck is friendly and a little crazy. Again, I think your MC needs a bit more of an arc to stand out. One suggestion, make him progressively more hostile on the phone towards the end of the story. Then, he'll both have a greater arc and the fire won't seem so sudden. For instance:
"My dad beats my mom. "She probably deserves it.
Do it better than that, in a more comical way, of course. It will add some character and foreshadow bad stuff to happen.
Prose--Easy to read. You have a tendency to not put commas at the end of an introductory preposition. I think you should fix that unless it's a stylistic choice that you want to stick with. But, I think it's jarring.
Dialogue--on the whole, easy to follow and natural. I thought it was fine. It did its job.
Theme--be careful not to shove it down the reader's throat. A few times, I wanted to gag. Allow the reader to read and examine your story for the meaning. It should be apparent what the message is, but give it some breathing room. Does that make sense?
Foreshadow--not really needed, but you could foreshadow the fire with one the posters in the beginning. Something like: "Light up someone's day!" would be good.
I might add in some line edits later. There were some minute things that I thought needed fixed. Too much to go into here.