Oh man... this is my kind of thread for sure.
1) The practice of throwing 20 pages of fine print at people, and asking whether or not we "Agree to the Terms and Conditions." Of course we're going to say yes, who the hell actually spends a second reading any of that?
2) Why a typical four-year college in the United States is hundreds of times more expensive than colleges in other parts of the world.
3) Why iced coffee costs more than regular coffee. It's coffee with ice. Freaking ice.
3a) Why a cheeseburger is like 50 cents more expensive than a regular burger. They are literally charging half a dollar for a single slice of cheese. What a ripoff.
4) The current practice of putting medical students through medieval sleep-deprivation torture, while expecting them to somehow effectively acquire the skills needed to become a decent doctor.
5) Bullying.
6) The human race's obsession with material wealth and status.
7) What is love? (Baby don't hurt me...)
8) Why women aren't allowed to propose marriage.
9) Boobs, why are they so awesome? xD
10) Why we are compelled to put more and more of our lives online, when it is becoming more and more obvious that NOTHING online is truly private. It doesn't matter how "secure" your information is: if someone wants it bad enough, they will find it.
Trust me, I can think of a lot more... complaining comes very naturally to me.