@lukestokes
This is awesome, this puzzle really got me thinking. My first answer was cup 4, but having a closer look at the blocked pipe made me go for cup 6 and there was no outlet, went further to choose cup7 not knowing the cup itself is having an outlet ...but in all sincerity, I never saw cup 8.

From your analysis, I think I was feeling so sure about my answers just as you said 
>we all think we're "above average," and we all want to latch on to an answer once we think we have it which resolves our cognitive dissonance. We're happy with ourselves and maybe even feeling a bit smug and superior to everyone else who "got it wrong."

I think you are right and I will really love to add this that we should all look at things closely before giving answer confidently, which I am also guilty of.

This puzzle really got me thinking about humans and how we see things from different perspective and how we arrived at our results...this is really helpful.

Thanks for sharing this.
Followed, upped and resteemed
@bekky