Besides, if you get the "SWINE" and don't die from it, it obviously makes your immunity stronger..
Common misunderstanding in this sentence. I'm not only picking on LFTL, just using her quote to explain something. I think you all may have seen Independence Day, in which there is a nice little anecdote to use for explaining vaccines:
Imagine the vaccine being the ship that crashed in Roswell in 1947. The scientists pick up the wreckage, analyze the alien ship and get a basic understanding on how it works. They aren't sure if the aliens will keep using those ships when they once come to Earth again, but they can assume that their technology still will be based on the one on the crashed ship.
Same goes for the flu shot. Your body recieves a dose of half-dead virus. Your immune system still see them as a threat (it's virus after all), and bombards it with whatever antivirus stuff they have got. In case of a normal illness, the virus would have been free to rampage while your body searched for the effective antidote, but now, it's half dead and can't harm a flea. Eventually, your body finds the correct antidote, obliterates the virus, and scribbles on its metaphorical notebook: "In case of this virus, use that antidote"
Back to Independence day, the aliens attack. We'll skip the part about destroying major cities, and jump straight to the part where the humans pick up the alien ship and use it to deliver a nuclear bomb to the mothership. The tools are there, and the aliens are defeated. If it hadn't been for that ship, the aliens could run rampant until the humans managed to shoot down a ship and use the same strategy, and by that time it could have been too late.
Again, same goes for the viruses. If you get the flu, your body has to try all sorts of antidotes before they find the correct one, but it you have the vaccine, it can simply open the metaphorical notebook and send the correct antidote without further ado. The outcome is the same either way, your body investigates the virus and eventually defeats it. But with the vaccine, it gets time to find the correct antidote before it gets to a stage of emergency. Without it, it has to do it while coping with the effects of the viruses, and the virus can wreak a lot more havoc before it is defeated.
Again, vaccine for me, please.