- Make everyone use the ISO8601 date format
- Have everyone drive on the right side of the road
- Eliminate the "sidewalk shuffle" by standardizing on always moving to the right
- Customer support lines/banks/etc must shift their opening hours slightly so that they are open outside of business hours, so that working people can use their services
- Make all instant messaging programs use XMPP, Matrix, or another open protocol
- Put the UK back in the EU
- Change world elections to be Alternative Vote, or similar
- Add another month and make all months shorter and the same length. Have an intermission period at the end of the year to iron out the remaining time. A la gormanuary.
- Delete America's guns, give America proper healthcare
- Standardize on Esperanto
- Replace Python with Ruby
- Make it so that Microsoft actually remembers my login session when I click "remember me" instead of logging me out all the time
This, I think, will fix most of the world's major problems.