4. The LatAm tension
Things could get awkward when U.S. diplomats run into some of their Latin American counterparts.
Brazil had a falling out with Washington over reports that the U.S. was electronically spying on the its president's communications. Both countries agreed to postpone Brazilian President Dilma Rousseff's state visit to Washington in October to a later date.
Venezuela isn't exactly happy with the United States, either. Last week, the government accused the U.S. of refusing to allow its president's plane to fly through U.S. airspace while en route to China. The State Department denied the claim, saying it granted permission for the plane to fly over Puerto Rico.
5. The no-show ... and the not wanted
Not all the 193 countries will be represented in New York.
Kenya recalled its envoy, Macharia Kamau, because Deputy President William Ruto has been on trial at the International Criminal Court for alleged crimes against humanity.
"We very much regret that he cannot be out of the country at the same time as the Deputy President," Kenyan State House spokesman Manoah Esipisu said in a statement.
The U.N. court accuses Ruto of plotting attacks that killed more than 1,000 people after Kenya's disputed presidential election almost six years ago. He denies it.
Another leader the International Criminal Court would like to get its hands on is Sudan's president.
He's wanted for genocide, war crimes and crimes against humanity for his alleged role in a five-year campaign of violence in Darfur.
But President Omar al-Bashir might show up anyway.
"As I've said numerous times, he has submitted a visa application. We're not going to sort through the considerations underway right now on that application publicly," U.S. State Department spokeswoman Marie Harf said Friday.
There's little the U.S. can do. As the host country, it's generally obligated to grant visas to heads of state, wanted or not.