I did think about the impact of my vote, of course. Many thinking people do. Most I know joke about how in their state (New York or New Jersey), their vote is irrelevant. My best friend likes to joke he is voting to cancel out his mother-in-law's vote. (They are diametrically opposed when it comes to politics). But I didn't think past the joke until I watched an amusing PBS video featuring Gordon Tullock. This is the video that changed me:
So why did I vote for so long? I remember the editor-in-chief at my first job used to badger us about voting. She was a liberal and I was a conservative then, so it was fun for me to listen to her advice and then vote for the guy she hated. And there, in those last two sentences, are the main reasons I voted: feeling good and not feeling bad. It was emotional, and largely subconscious. I voted out of guilt because I didn't want to be the kind of deadbeat my editor derided. I voted for pleasure because it felt righteous to support my side and take a stand against the other side. (Even if their guy won, I could say snarky things like, "He's not my president.") Sometimes it also felt good to be part of a great democratic process that others would literally die to have in their miserable countries. Etc.
After I converted to libertarianism, though, voting became much less attractive. (As P.J. O'Rourke put it: "Don't vote: It just encourages the bastards.") I realized the above is all brainwashing, that I'd fallen victim to skillful mind manipulators. After that, all I was left with was the weak guilt my editor had tried to instill in me. It dissipated quickly.
Now I call people out on this issue. I ask them why they vote, and I make them give me a thoughtful answer. Some have enough self-awareness to immediately identify emotional reasons. Good for them: It took me longer to get there. Most, though, cite all the usual strident nonsense. They say thing like, "Well, if you're not part of the solution, you're part of the problem." (Groan. Eye roll. End of conversation.) Or, "What if everyone followed your example?" (I tell them that I wish I were so influential). Lately, someone even tried a thought experiment where it was 2000, I lived in Palm Beach County, Florida, and the Bush v. Gore thing came down to my group's hanging chads.
For those folks, I recommend reading this 2004 Steven Landsburg article from Slate. Sub-headline: "It makes more sense to play the lottery." Well put, Mr. Landsburg. (I'll explain why I don't play the lottery another day.)