This happened about two years ago. At the time, i had heard rumors about a party being set up for those in my class in secondary school and was very interested to join. So, i decided to ask around and finally got the names of those planning the party and decide to ask them if i can come and offer my help, thinking of a simple yes or no answer. Instead, i receive no answers or info about the party until the day it was supposed to happen( even this i found out from another friend who wasn't even planning it) or if i was even invited or was to help in some way. At some points some people  directed me to someone else , and then it would go nowhere with the again other person stating "I'm not planning the party, ***** is! Ask him/her!" And then directing me to another person who would repeat it over and over until the day before the party.

At this point, I'm about 70% sure they don't actually want me to go to the party, and get pretty pissed at both being left out and most importantly being bounced around and treated like a fool. So, seeing as i was due in the area for some errands, i decided to gatecrash, and act dumb to screw their party up. So I did it, only telling my good friend that told me in the location in the first place, and ONLY leaving to gatecrash at about 3pm i get a msg telling me not to come, less than 1 hour before the party was due to start. Of course, at this point im indignant, and go there anyways, wishing my good friend a happy birthday (the party was to celebrate those that had their birthdays that month) and after taking a small 'greeting' parade and some trolling left to do the errands.
AITA for doing this? What else should i have done?(In hindsight, i do feel it was petty, but those people really pissed me off.