they are probably trying to be rebelious, or stand out in the crowd

Maybe the other guests saw what he was trying to do and decided to completely ignore his boycott attempts by giving him compliments on his "costume"?

must be a hipster thing

That's what I thought too! :)

Sounds more like a dick thing to me.

Because they want everyone else to know how much of a unique snowflake they are.

Yup for sure OP is a hipster. Damn hipsters.

I agree. OP is a party pooper. Why go to a party with a theme just to not participate in the theme? All it does is ruin other people's time.

What about the party did you find boycott-able? Was it the fact that it was 80s themed? Because that's a little odd.

Yeah people who choose to boycott something in order to get attention and still eat all the free food are such assholes.

Maybe they didn't have the money for it. Maybe they are tired of 80's themed parties. That is totally legit. But "protesting" is just rude and stupid.

Thank you for that observation, Sherlock

Not a problem lieutenant sarcasm

Keep digging Watson...