Spoilers Ahead!
Goat Simulator 3 has lots of quests that can be completed! They help you progress the main story and earn points to buy new customization options for your goat. They are also just fun to do. These quests include:
Build a portal that leads to Ikea.
Play Doom except you fight grandmas with bazookas.
Help ballerinas spin faster so they can become tornadoes.
Run for president and win by dragging people into your voting booth.
Win a cosplay contest by making a really cool outfit everyone will want to wear.