- Gay marriage will be legalized everywhere in the developed world; think of the way we look at people who opposed interracial marriage decades ago, that is how future generations will look at those who oppose gay marriage now
- Soccer will be the most popular sport in the US and the US NT will have won the World Cup
- Printed media and books will have disappeared
- The EU will be a federation
- People will complain about how "everything was so much better in the 2010s"
- The US will no longer be the world's sole super power; global politics will be dominated by a West vs. East power struggle with US & EU on one side and China & India on the other
- Medical science will have taken major leaps and we will be amazed at the kind of diseases that killed people back in 2010 (such as cancer). However, new threats will come in the form of mutated bacteria and dangerous viral infections
- Food: much more awareness of what is in our food, most if not all food will be organic and (if possible) locally produced
- At least in the EU, all cars will be electric and using gasoline for cars will be illegal and considered backwards
- Developments in quantum mechanics will make it possible to save and transfer data without leaving any trace
- Cash money will no longer be used
- Islam will have taken over Christianity as the main religion in the world
- The death penalty will finally be abolished in the US and people will be amazed that it took so long
- Artists that people will still remember in 2030: Beyonce, Lady Gaga, Adele, Eminem. Somehow I doubt Rihanna will have a lasting impact despite her impressive record sales. There's nothing really memorable about her or her songs
- Borders in Europe will have shifted once more. Some possibilities: Belgium splits up, Scotland proclaims independence, the Republika Srpska in Bosnia joins Serbia, Catalonia proclaims independence, the Russian minorities in Eastern Europe proclaim independence or choose to join Russia, etc.
- Continued political polarisation, fascism will become a political factor of significance again all over the world to counter increasing globalisation
- Leggings and yoga pants will be out of style (finally!)
- There will be many more women in powerful positions, especially in politics
Just a few I could think of