10 Incredible Singleplayer Features You Can Only Unlock By Playing Multiplayer
Sometimes the only way to have fun alone is by bringing other people along!

The line between single-player and multiplayer games is usually drawn very clearly. Developers like to separate the two game modes so that, regardless of their preference, every player will find a game mode they like.
However, it turns out that not every game is fond of this approach. Some of them, despite having distinct modes for single and multiplayer, will only allow you to experience certain things if you play them both!
Although the content is meant for single-player modes only, to access it, you'll have to cooperate with other players in multiplayer.
This might sound frustrating to those who prefer to play solo, but on the other hand, this bizarre blend of two radically different game modes can make for an interesting experience where you see progress from one mode you play bleed into another.
You might be able to gather more resources by collecting them in online matches, gain additional dialogue options by playing with friends, or even access a full unique ending by letting other people impact your game.
It's definitely a weird blend, but it's guaranteed to only change your single-player experience for the better.
10. Touring For Goodies - Sims 3

The Sims games aren't really built with multiplayer in mind. The whole point of the series is that you play a god messing with your Sims, so multiplayer doesn't really work well with this premise.
Still, in Sims 3, Maxis tried to implement some multiplayer features via touring.
Introduced in the Showtime expansion pack, touring allows your Sims in the entertainment career paths to visit other players' games for a live performance.
The process requires both players to be connected to SimPort and then setting up the show and venue in the host's world. It is the only Sims 3 feature that uses online play so directly, and while it can be a bit of a headache to set up, accepting and sending Sims on tours grants both participating players some great rewards to use in their regular single-player save files.
The tour provides lifetime achievement points, simoleons, and, more importantly, it unlocks exclusive outfits and objects that you cannot normally access in single player.
So if you want to get some new goodies to play with, you better pray you have a friend with a SimPort account that still plays the game in 2025...
Good luck!