I've spent a lot of time thinking about this, and probably the absolute worst change in our normal daily lives after ET lands and gets out of the spaceship is that
All of our stars are no longer famous.
Now we are some miserable little podunk planet in the middle of nowhere. Who in the universe cares about Elvis Presley? The Beatles? Hardly anyone.
In fact we won't be able to call them stars anymore. Not until an earthling is famous on two or more planets, perhaps even two or more solar systems, can they be considered a star.