Pros to the Flu Shot:
-Covered by my health insurance premiums.
-Solidarity with other flu-shot getters. You know what I mean. People are always asking, "Did you get your flu shot? I got mine!!!!!" and then I say, "Oh, no, I've never had a flu shot..." and then they say, "Oh!!" and inch away slowly. This could also be a con, because clearly people aren't that confident in the flu-shot effectiveness if they're afraid of my un-immunized self. So actually, this one doesn't count as a pro.
-10 minutes that I don't have to be working, more if I do all the other health fair stuff at the same time. But I like my job, so maybe this isn't a pro either. I'll let it slide, but it's kind of weak.
Cons to the Flu Shot:
-Last time I remember having the flu was my junior year in high school. In the ensuing eight years I have been flu-free despite my exposure to co-ed university dorms, public transportation, and myriads of germ-laden children.
-Only covers 70-80% of flu strains. I have terrible luck. I would get each and every one of the remaining flu strains back-to-back, and then I would get fired for being disease-ridden and also weird.
-Possible injection of government-issued nanotechnology designed to read my mind.
-Furthering of paranoid ideas derived mostly from dystopian novels and science fiction television. There probably aren't nanobots in the flu shot...but WHAT IF THERE ARE? Then I set myself up to be a government (or alien!) science project. My ultimate demise would be my own fault. I could never hide on a farm in the middle of nowhere because they would find me and steal my brain and kill all my sheep.
So that's two pros and four cons. I think I've worked this out rationally.